What North American accent do you have?

There has been a lot of discussion over on the Forensic Linguistics mailing list about the following quiz to identify what North American accent you have. I haven't thoroughly analyzed the responses having to do with the accuracy of its "algorithm", however the sense that I took away from the debate is that it works more than well enough to be impressive but is not completely infallible (which seems to be the case for many attention-grabbing items on the Internet). Plus, it is a good bit of fun... Enjoy!

Aggressive speech detection and CCTV

c|net reports (along with many other sources) on a company with a very appropo name, Sound Intelligence, that has introduced a CCTV system product that includes an audio-based automatic aggression detector called SIgard. One or more microphones are co-located with a CCTV camera. A software-based algorithm monitors the incoming audio stream and "detects" aggressive human speech. When the system makes a detection, it alerts the CCTV operator staff to attract their attention to that particular camera and location. Only at that point may the CCTV staff monitor the audio for that camera and not before, according to the company.

The company is based in the Netherlands and has deployed systems there. They are now entering the market in the UK.

This technology was briefly mentioned in an interesting debate on the BBC's Moral Maze radio program this week. The topic was the "surveillance society" and the program is well worth a listen for those interested in the general topic. I should note that I detected quite a few inaccuracies in the debate, so don't take everything in it at face value.

Archiving digital evidence

Popular Mechanics magazine has an interesting article on the issues involved in long term digital storage and retrieval. These issues are of particular concern in forensics - how do we safely store evidence in digital format for 20 plus years and also make sense of it when after retrieving it, despite the ravages of time and the march of technology?

To put things in perspective, when I was in high school (years 10-12 for those of you from other countries), we used slide rules in my electronics courses. For the first few years at university, we used punched cards for data and program input (this was how you programmed the venerable workhorse IBM 360/370 computer back then). Computer data storage in those days was either an analog audio cassette tape (for low-end machines, such as the Commodore computer) or tape reels. To move quickly to the present day on this trip down memory lane, now we use thumb drives, memory cards, and RAID systems, to name a few current alternatives.

There is also the issue of possibly needing to maintain the computer operating systems to "address" the data and/or programs - they've changed rapidly too. Add proprietary standards on top of it and you've got the makings of a very big problem.

Some important things to remember on this subject are:

• Use media that is certified to last for at least as long as you are required to retain the data, preferably longer. I advise staying away from tape myself, given the number of cases of dry rot and self-erasure I've encountered. CD and DVD are the current favorites, but don't confuse a short-term cost savings with long term viability - buy "gold" disks. Also see NIST publications, such as this one, for tips on archiving CD and DVD media. The environment in which you store your media matters!
• Render your results into "data" and store the data. Don't (only) store the data as part of a "project" file that will then require running the program to get the data back out. The same goes for the audit trail. Don't rely on (only) a "project" file to store the steps you took in processing the evidence.
  
• Store data in non-proprietary formats, preferably ones with wide support. In the case of audio and video data, I recommend WAV and AVI, respectively. For textual data (reports, audit trails, etc.), .TXT is a good choice.
  
• Periodically perform spot checks to ensure archiving and retrieval procedures are working properly. It only takes one mistake to ruin a lot of evidence!

Please note I am not trying to say that you should never use proprietary data, project files, and such. What I am trying to get across is to not be single-threaded on them. In other words, go ahead and store your report in Microsoft Word (R) but also store a copy in TXT, just in case. Go ahead and store the project in your audio or video software, but also render and store a WAV or AVI. For that matter, you should burn an audio CD (i.e. CDA format) or video DVD too, so that an operating system is not required for playback.

In closing, effective archival of data is a tough problem, but one that has been around for a long time in one form or another - consider cave paintings and hieroglyphics as examples. We won't "solve" the problem even now, but it is our responsibility as professionals and keepers of the public trust to take reasonable and effective steps to maintain the integrity of the evidence.

Robbers steal cash and video evidence

Two armed men robbed a convenience store in Arlington, TN (USA) on November 19th and, after noticing the store's video security system, also took the video tape cassette showing the crime. There were several eyewitnesses and the robbers were not wearing masks when they entered the store. Police have appealed to the community for assistance in solving the crime.

(Hat tip: Eyewitness News 24 and CW30)

US and Canada to share crime scene forensics data

According to this Associated Press (AP) report, the US and Canada have signed an agreement to allow the real-time sharing of crime scene forensics data.

Collection and use of security video evidence after a crime

The Edmonton Sun has a report on the Michael White murder trial. Mr. White is accused of murdering his wife, Liana, and abandoning her body in her white SUV. City police presented evidence consisting of images recovered from a security video camera at a local pub and an analysis thereof. The images, with their timestamps, show a white SUV being driven down the road where the victim's body was found during the relevant time frame and some minutes later a man of similar build to Mr. White jogging back down the road. None of the images are ID (identification) quality to be sure, but the video was apparently analyzed carefully to see if there was a match with the vehicle and to see if the times and distances were consistent with the prosecution's accusations.

Besides not being widely reported (at least as of now), the other reason I am posting this is to point out how the widespread use of security cameras has caused a change in investigation procedures and workload. Now, after a serious crime has occurred, law enforcement personnel perform a sweep of all security cameras within the area and collect the video on them for analysis.

You might not think it so, but the collection itself can be a major task. In the old days, only a few places generally had them and the ones that did recorded to video cassette. Now, with the advent of hard disk based recorders, just getting the video off the recorder in a way that preserves the original quality is challenging. On top of that, coping with the proprietary codec and playback software is an additional challenge.

Aside: "Codec" is short for coder-decoder, which is the algorithm that translates the raw video into a digital format, which is often of much smaller size and contains significantly less detail.

This brings to mind the July 7th bombings in London, UK. Because the bombings occurred at multiple locations spread across the center of London, thousands of recordings had to be collected and analyzed. This required an incredible amount of effort. In the true spirit of international law enforcement cooperation, a colleague of mine from the USA was detailed to the UK for a year to help out with the work load. You've probably seen some of the images that they found. They not only tied the suspects to the bombing but provided other information as to their methods of operation. So, although the explosion of digital security video camera technology has not been without problems and has also increased the workload substantially, there are significant benefits that has come with it - benefits that may include bringing the correct person to justice for the slaying of Mrs. White.

Note: I would like to make it perfectly clear that I am not making any judgments or claims about the quality or validity of evidence against the accused in this case. As is said in the USA, the "accused is innocent until proven guilty". In any case, evidence may be tossed out, an alibi may be presented, or other events may result in the accused being acquitted, either initially or on appeal.

DARPA wants a 10-gram long range IR camera

DARPA has released a broad agency announcement (BAA) for a program with an ultimate goal of a SWIR (Short Wave Infra Red) camera weighing only 10-grams total - that means 10-grams for the camera, lens, detector, and electronics. Fortunately, the winning contractor lab(s) won't have to promise to reach that goal in the first phase!

DARPA has crafted the goals so that they become more and more aggressive as the program goes on (as usual). There are also different requirements for medium and long wave IR camera systems as well as different applications (miniature UAVs and head-mounted).

That being said, the goals are beyond challenging. A report at Defense Tech has a quote saying that "it will take a radically new approach". I'd say that is an accurate assessment myself. It will be very interesting to see what the contractor labs come up with.

The information packet can be found here (PDF download).

(Hat tip: Defense Tech)

Online store

Well, I didn't get it done in the 5 minutes that the review I read suggested was all that was necessary, but after a couple of hours I had Amazon's aStore up and running for this blog. Don't take this move wrongly though - this is not turning into a commercial blog, by any stretch of the imagination. I have no fantasy of this being a get-rich-quick thing. If it helps pay for my broadband bill each month, I'll be more than happy! As things go with me, what it will all probably mean is that I will lose money in the long run - as I find books that I haven't gotten around to buying already. For instance, just today I ordered a copy of Temples of Sound (a book about the famous sound recording studios in the USA).

As part of this exercise, I added in entries for my favorite books in the field of audio and video forensics. Most are not forensic books themselves as there aren't many in this niche discipline, but instead books on recording, biopsychology, filtering/processing, and the like. All in all, I'm not displeased.

That being said, there is room for improvement from my perspective. For instance, it would be much more helpful to either allow more recommendations OR boolean search terms when setting things up for what is displayed (like the OR I just used).

Anyway, feel free to let me know what you think, either online as a comment or offline via email (see the email link at the top of the links section, but don't forget to replace the anti-spam text).

Other blogs of note

I wanted to pass along some links to other blogs worth spending some time with. Two are related to forensics and the other is by the same guys who wrote "Freakonomics", a very interesting and approachable book on economic statistics applied to the everyday world. They are:

• Psychology and Crime News
• Forensic News Blog
• Freakonomics

Enjoy!

Update on DARPA's Automatic Speech Recognition & Translation Project

The AP has a very interesting article about BBN Technologies' work on DARPA's speech recognition and translation project, called Global Autonomous Language Exploitation (GALE).

There are two other companies being funded, along with BBN, for the work - IBM and SRI International. All three are being supported by LDC (Linguistic Data Consortium, University of Pennsylvania), which is an open consortium founded by the USG (United States Government) to create and distribute speech and text databases, as well as other types of resources, for language research.

The AP article is easily understandable by non-specialists, while still being interesting for those who do this for a living.

The researchers are only one year into a five year funded effort, so it is still early days. It will take some significant breakthroughs to accomplish what Dr. Joseph Olive, the DARPA program manager heading it up, has set out for the goals - they are well beyond merely challenging, but that is what DARPA's mission is supposed to be about.

(Hat tip: Ars Technica)

Latest version of Audacity can save multichannel wav files

It is still in beta, but Audacity 1.3.2 is available for download from Sourceforge.net and from an afternoon spent with it on a Windows XP SP2 machine, I can say that I like it better than any other audio editor I have tried (and I have tried many). Plus it is open source and free! Well, I do have one beef with it - it doesn't support DirectX plug-ins.

I upgraded to this version for the simple fact that it now supports saving (exporting, writing, or what ever you might call it) multichannel wav files. All other audio editors these days seem to have been streamlined to support only CDs (i.e. two channel), surround sound (5.1), or similar mass market formats. Of course, if you are messing about with microphone arrays, being able to save multichannel files is more than a convenience. Adobe pulled this feature out of Audition (editor's correction) (formerly Cool Edit), much to my chagrin. Things haven't been easy since.

You do have to configure Audacity properly first, however, as it won't allow it in its default state after installation. To do this, go to Edit/Preferences to pull up the panel for setting the application's preferences. Then select File Formats and tick the radio button labeled Use Advanced Mixing Options. When you get ready to save your multichannel file, simple choose File/Export As/Wav and it will pop up a handy panel to let you select which track gets recorded to which channel. Very nice.

This version also seems to be faster at loading and working with multichannel files. All editors that insist on displaying the time waveform (and that would be just about all of them) go through the entire file at first load. This can take a long time when you are talking about some of my files - 64 channels, 24 bits, and at least 16kHz sample rates.

BTW, you can also select how many channels you wish to record to under the I/O heading in the Preferences Panel. I haven't tried this with an external digitizer yet, but I will do so soon on a MOTU box.

(Notes: "Audacity" is a trademark of Dominic Mazzoni. Audacity is licensed under the Creative Commons Atribution License Version 2.)

Maintenance of audio/video equipment

I will use this news report to highlight a continuing issue in the audio and video forensic community - poor maintenance of equipment and detrimental penny-pinching on electronic media. All too often, equipment gets purchased and installed in interview rooms only to then not be maintained until it breaks. I don't know if this was in fact the case with this particular incident, but the quote "Technical problems caused the tapes to have poor audio quality" seems to point in that direction.

Experience suggests that one or more of the following common occurrences could have happened:

1. the record head was out of alignment, dirty, or magnetized;
2. that someone had tampered with the equipment (suspects brought in for interviews often try to sabotage the recording equipment while the detective is out of the room, such as by jamming a pencil into the microphone, so maybe the microphone had been somewhat damaged previously);
3. that inferior quality tapes were used (just because you can get 100 tapes at the local big box store for $3 doesn't mean they should be used for what could end up being used as evidence);
   
4. that the tape had not been changed recently (if their policy was to reuse tapes);
5. there was an electrical power grounding problem (causing hum);
6. the recorder had some other fault (bad tensioner maybe, but then the video would have been out of sync also); or
7. the suspect was too far from the microphone to pick up clearly (doesn't sound like the case here though).

I'm curious to know if they attempted forensic audio filtering or not. Depending on the nature of the problem, it might be possible to recover the audio, although it may not be important enough to either the defense or prosecution to justify the effort. Welcome to the sometimes messy, but real, world of audio and video evidence.

Complicated forensic case against target using counter-surveillance

Scotland Yard had quite a large, complicated case on its hands when it tried to arrest, charge, and convict Dhiren Barot, 34 and from London, reports the BBC. Barot was apprehended while plotting terrorist attacks against the UK and USA. The following quote will give you a sense of just how involved a case it was:

Codenamed Operation Rhyme, it saw 4,000 garages and lock-ups visited and the seizure of nearly 300 computers and around 1,800 items of discs, CDs and removable storage. The case also involved a wide range of investigative methods, including forensic linguistics, to prove the authorship of documents, facial mapping, computer forensics and handwriting analysis.

Barot also employed counter-surveillance on a routine basis, according to the report. He

rarely stayed anywhere for more than a night, used a variety of different vehicles and hardly ever used mobile phones. He would also perform sudden manoeuvres in heavy traffic or circle roundabouts to make it more difficult to be tailed.

Barot was sentenced to life in prison.

Forensic Positions

I'm passing along the following position announcements posted to the Forensic Linguistics List:

Research Assistant/fellow (2 posts), Eyewitness Memory, University of Aberdeen (UK)
http://www.jobs.ac.uk/jobfiles/KE052.html
Applications are invited for one Research Assistant position and one Research Fellow (two posts, each for 3 years) to work on a research project which aims to develop objective and effective means of assessing the extent to which a particular eyewitness memory report can be relied on as evidence. Closing date 13th November.

Teaching Assistant (0.5fte), University of Leicester
http://www.le.ac.uk/personnel/jobs/e2994a.html
Applications are invited from Psychology graduates with sufficient knowledge in forensic psychology or related areas for a half-time post to support the School's three distance learning Masters courses in Forensic Psychology. There will be an opportunity to register for a higher degree by research. Closing date: 16 November 2006.

Criminal Justice Faculty-Social Sciences, Metropolitan State College of Denver (US)
http://www.academiccareers.com/cgi-win/JobSite/SendJob.exe/ACO/?14535
The successful candidate will teach 12 hours per semester in the Criminal Justice and Criminology Department. Closing date: 7 Jan 2007

Forensic Psychology in the news

First off, let me say that Forensic Psychology is not my specialty. Second, I should point out that politics can come into play in any discussion involving interrogations (and for that matter, surveillance), most particularly when reported on by the news media or commented on by politicians and activists.

Be that as it may, the Cape Cod Times has a report from an on-going trial in which forensic psychology and interrogations are currently front-and-center. It seems to have a leftward bias from my reading ("forewarned is fore-armed", as they say), but is interesting nonetheless.

The CSI Effect

The Pittsburgh Post-Gazette has a excellent article on the "CSI Effect" on law enforcement agencies, the judicial system, and the public. Here are some brief excerpts:

Police processing crime scenes now over-collect evidence, and prosecutors order unnecessary tests to make sure that every eventuality is covered, Mr. Houck said. Defense attorneys, too, get in on the act, he continued, by demanding perfect science all the time.

and

... Mr. Houck cited jurors who have said they found defendants "not guilty" because there was not enough physical evidence presented, even if there was overwhelming circumstantial evidence.

and

... make the public believe that the scientists' resources are unending, Mr. Houck said. The labs on television have unlimited budgets and access to the best equipment in the world -- something that is uncommon in the real world.

According to a study by the U.S. Department of Justice at the end of 2002, there was a backlog of more than half-a-million cases in crime labs across the country.

I encourage you to read the entire article, which only runs about a page but its every word is "spot on", as the British say. My compliments to Paula Ward of the Pittsburgh Gazette for her reporting from the perspective of real-world forensic science.

Tone deafness linked to right frontal brain area

The current issue of the Brain science journal presents the results of a study into tone deafness (congenital amusia) using MRI. The results pinpoint the right frontal area of the brain's white matter as the area that is different between normal hearing people and those with tone deafness.

The work was performed by researchers from the Université de Montréal, the Montreal Neurological Institute and the Newcastle University Medical School.

Press release on Eurekalert is here.

Kentucky RCFL opens new lab space

WFIE reports on new lab space for the Regional Computer Forensic Laboratory (RCFL) in Kentucky. Despite the name, an RCFL typically does much more than just computer forensics. Audio and video are called out explicitly in the report (hurrah!).

UPDATE: WAVE online report with significantly more info.

Example of forensic video analysis

If you are interested in seeing an example of a forensic video analysis report for a real case, check out this KXLY (Spokane, Washington State, USA) news report and the accompanying PDF of the forensic report. There is also supposed to be some audio and video excerpts linked to from the news report, but I could not get them to play; maybe you will have better luck.

The forensic examiner who did the work was formerly with law enforcement and went from there to work for AVID, so don't be suprised to see a lot of references to that particular manufacturer's hardware and software.

Disclaimer: Any mention of any particular company should not be construed as an endorsement of their products. The motivating reason for the creation of this blog was to counter the commercial bent of the overwhelming majority of blogs that address audio and video forensics.

Where will surveillance cameras go next?

A rough history of the deployment of surveillance cameras might go something like this: bank lobbies, access portals, airport parking lots exits, ATM machines, city centers (in Europe), shopping malls, bars/pubs/restaurants, and communities (in USA). So what will the next stage of deployment be? Homes...

Music research using subjects with synaesthesia

Dr Jamie Ward, of the University College London (UCL) Department of Psychology, and others there have been working on music research using human subjects with a rare condition known as synaesthesia. Synaesthesia is is a neurological condition in which two or more bodily senses are coupled (Wikipedia) and manifests itself as, as examples, seeing images when music is played or experiencing a taste when reading a word. Fascinating, isn't it? To find out more on synaesthesia or participate in the research (if you have this condition), see the UCL Psychology site.

(Hat tip: scenta musci and news)

Human hearing, music, and evolution

The Boston Globe has an entertaining popular-science article on human hearing, music, and evolution.

Single-pixel camera

New Scientist has a write-up on a new camera technology to be presented at this week's Frontiers in Optics conference by researchers Richard Baraniuk and Kevin Kelly of Rice University in Houston, Texas (USA). The idea is to replace the multi-pixel image sensors currently used in digital cameras with an array of micro-mirrors that randomly reflect the light hitting them onto a single photoreceptor (i.e. light sensor). A follow-on processing stage then sorts out all the digitized light information to construct an approximation of the original image.

It is claimed that this can reduce overall power consumption of the system as well as compress the image data. Not to be too critical of early-stage work, but that seems like it will require one or more break-throughs and a favorable nod from the ghost of Mr. Murphy (of Murphy's Law fame).

Another idea that the researchers put forward seems to be a more workable application of the technology - using it with sensors that may not lend themselves easily to large arrays, such as terrahertz or ultraviolet single-element sensors.

Informative animation of Middle Eastern history

Due to the information war aspect of the ongoing War on Terror, it is particularly helpful to understand the history of the region. Maps of War has an animation entitled "Imperial History of the Middle East" that I found to be accurate, informative, and unbiased - at least as far as I could discern.

Astrophotographer takes amazing picture

This picture will probaby be all over the Internet soon, but I still think it is worth blogging about here. A French astrophotographer named Thierry Legault took this image using a (serious) hobbyist-grade, ground-based telescope with digital camera attached. We've all been spoiled, maybe even jaded, by the Hubble Space Telescope images in recent years, so it is nice to see Earth-bound telescopes accomplishing amazing things as well. This version is reduced in size, but if you follow the article link (below), you can see an enlarged version that lets you see the Space Shuttle Atlantis and the International Space Station (ISS) against the Sun. It really gives one pause to consider the relative sizes of the objects considering that they are some 93 million miles (150 million km) apart!

Of course, this was not taken with typical mass-produced (Chinese-made) optics mounted in a plastic tube. I haven't seen the specifications of his set-up, but the cost mentioned in the newspaper article (5,000 GBP or a little under 10,000 USD) probably means lambda 6 or better glass (that was tested, not "claimed", to be lambda 6, as some disreputable distributors and manufacturers often do).

Aside: By using lambda in this way, I mean the measure of the wavefront integrity of the light as passes through the telescope. The closer it is to perfect the higher the number is. Lamdas of 1 to 3 are what you expect from mass-produced consumer-grade scopes. Lamda 6 from serious amatuer scopes. Lambda 12 is military grade. And lambda 20 is simply amazing to look through. High lambda telescope optics usually come from Russia, although I have also seen high-quality binocular assemblies from Japan. My comments are based on my personal experience and if you have a different opinion, please speak up as I am always interested in learning more about high-end optics and astronomy.

Taken all together, good quality glass, good quality digital camera, probably some image enhancement (frame averaging), decent weather, perserverence, and a keen interest in astronomy combine to give us this eye-catching image. My congratulations go out to Mr. Legault.

(Image source: the Daily Mail (UK))

Camera obscura

I am one of those parents who occassionally wishes he could be his own kids some days. My oldest two (boys) went to the local science museum this past weekend and attended a very interesting session on camera obscura (WiKi page here). They even made drawings on tracing paper and transparencies - very cool!

Sigh... and I had to be on business travel (again)...

Tamper detection

How do you tell if audio or video evidence has been tampered with? If protections were built in before hand, such as with watermarking, a CRC (cyclical redundancy check), or hash (e.g. MD5), it is easy. If not, then what? This popular technical media article from CNET on tamper detection for photos (photographs) gives a decent overview.

Lossless Audio Blog

A professional colleague (and friend) in the UK recommended that I check out the following blog: The Lossless Audio Blog. It is described as:

Lossless Audio loss·less au·di·o Pronunciation: 'los-l&s au·di·o Function: adjective 1. occurring or functioning without loss 2. A term describing a data compression algorithm which retains all the information in the data, allowing it to be recovered perfectly by decompression.

I have added it to my own RSS reader just so I won't miss anything. I hope you enjoy it too.

(Hat tip: Greg G)

Recovered video evidence a significant part of a terrorism case

I've posted multiple times about recovered evidence. In summary, it can be the best and the worst evidence - best for value and worst for the quality of what you have to work with. Here is a news report on a case where it plays a significant part in an effort to disrupt terrorist operations.

On an audio/video recording broadcast on TV, the defendent says in Arabic that:

he wants to take revenge for the injustices that Muslims undergo across the entire world. Police found the video tape when he was arrested last October.

The video's message is directed at "the Muslims in Europe, my parents, my brothers in the jails of the despots and the government and people of the Netherlands".

The defendent's words speak for themselves.

Decibels

A professional colleague (and friend) recommended that I read the Wikipedia page on decibels (dB) - and it is indeed very well done.

(Hat tip: Tom D)

Study Finds Sharp Drop in the Number of Terrorism Cases Prosecuted

The New York Times has published an article on the results of a study conducted out of Syracuse University that claims to have found a drop in the number of terrorism cases prosecuted in the USA since 2002. The stated causes are a lack of evidence and other legal problems. Not taking at face value what one reads in the newspapers is prudent, particularly in light of recent plagarism, photoshopping, and other incidents, along with the (sometimes acknowledged, but often not) biases of the news media. However, that being said, there are likely some important truths buried in the study and article for those who care to dig for them.

One thing that came to mind while reading the article is that terrorism has created a dilemma for judicial, law enforcement and security agencies alike - how can we 'stop' terrorism? Can we treat it like a typical law enforcement function (i.e. wait until after the crime occurs, collect forensic evidence, investigate, and prosecute)? That fits in with our modern day western ideas of justice, but it means that innocent people die (I am using the term "innocent" in a western context, not in the context used by militant Islam).

If we want to prevent a terrorist act from occurring in the first place, that means that there will be a lot less evidence, by definition. That is where the trouble begins - going to trial (in court and in the media, unfortunately) without gunshot residue on the suspect's hands, so to speak. Instead, the evidence is about possession and conspiracy - which often is not nearly as damning as the aforementioned gunshot residue or, now, DNA is to a general public 'trained' by the CSI television series. But prosecutions based on possession are not a first, by any means - for instance you can't carry a set of lock-picks in the USA unless you are a locksmith (or law enforcement officer trained as such, loosely speaking) or possess child pornography. However, conspiracy is a difficult thing to prove in a court of law; it often looks less convincing to the public, and it gives the defense and its supporters more room to raise doubts about the quality or integrity of the evidence (which is their right, under western-style legal systems). On the other hand, it does increase the chances that an innocent person might be caught up in the web of conspiracy; in the cases where errors may creep in, we trust our system of checks and balances in the judicial process to catch most, if not all, of those. (It is not feasible to implement a "perfect" system, but we do want to get as close to that as practical).

But what else can we do? If we go the intelligence-led disruption route (i.e. we do not try to prosecute and instead focus even earlier in the "chain" on disrupting the cells, networks, and plans in their formative stages), there is even less forensic evidence that will stand up in court. Now we are talking about association, membership, or being a possible threat to the community. That brings with it even more problems than prosecuting cases based on conspiracy and possession. What does the government do then? Deport the suspected terrorist? To where? Most of the places they come from give the civil rights activists apoplexy at the thought of sending them back, but likewise the activists are against detaining them indefinitely instead. I got acousted on the street not long ago by just such an activist, who insisted that detained terrorists who could not be convicted in a western court of law should be released back into the local community at large. My response was to suggest that was a fine idea, as long as he would agree to take them into his own home first.

Now, notwithstanding my attempt at wit, I believe in and respect civil rights and due process. However, I do think it is disingenuous for political activists to ignore the complicated issues involved in disruption operations and the inherent tradeoffs involved. It is just not a serious proposition to release all suspected terrorists - not if they are still considered dangerous by reasonable, informed people - even if it can not be proven in a court of law. What will the public say, and what will the moral culpability of a government be, if they go on to commit acts of violence? "You knew that they could be a danger to the community and you released them?!"

This is probably the right point to note that as a practical matter, we can not simply "eliminate the causes of terrorism", no matter how ideal a solution that may sound like. The lessons of history teach that there will always be someone out there who will take offense at the slightest provocation (intentional or not) to use it as a justification for their actions. If you combine that with Islamist beliefs about the Houses of Islam and War, including the return of all lands formerly under Islam to its dominion, and western decadence, it appears impossible to eliminate the causes of Islamic terrorism through negotiation or appeasement.

Some of the grey-haired wisemen say that the only strategy that will work is a combination of prosecution, where possible, and disruption, where not, to keep things damped down (and thereby minimize the loss of life and limb) until this generation of "militants" grows old enough to mellow out. That may be a pessimistic, alarmist, or overly geo-political observation, but it seems true nonetheless.

Getting back on my earlier train of thought, what does all this mean for forensic evidence? Well, there are some patterns in how forensics has changed in the last several years - computer forensics has become increasingly important, for one thing. Why? Others have said that, besides computers' obvious increasing penetration into every facet of western life, it is because computers are a medium of choice for communication amongst the members of the terrorist networks, their support networks, and religious/political base. So, forensic examiners will go where the evidence is. Expect to hear much more about computer forensics over the coming years, but also expect audio and video forensics to continue to play important roles, even if they aren't the flavour of the day, so to speak. After all, seeing and/or hearing the suspect implicating himself or caught in the act, such as through video-taped last-will-and-testaments and security camera images, is no less convincing evidence today than it was before computers.

A cool generation going deaf?

Here is another article, this time in the New Straits Times, on how the iPod generation is damaging their hearing by playing too loud volumes directly into their ears (using earbuds). I've blogged on this subject myself before, but the whole story is not being told - the ear has a self-protection mechanism built in. The stapes (one of the three bones of the middle ear) can actually pull back (decouple) from the cochlea (the inner ear) in response to loud sounds, thereby protecting it from damage. Unfortunately, this protection mechanism degrades as we age, so it functions best when we are young (and stupid). I'm not aware that the degree of protection has been thoroughly mapped against age, but it may be that a late-teenager or young twenty-something can get away with listening to some rock-and-roll at loud volumes but I wouldn't recommend it for anyone older, and that includes aging hippies - that would be just asking for trouble.

What do Mozart, Beethoven and Steve Vai have in common?

Music and, it appears, a positive influence on brain function. Predictably, after all the hype about the Mozart Effect from a few years ago, some researchers wanted to see if the effect could be replicated with rock music. So, they ran a study comparing the problem solving efficiencies of students while listening to silence, Beethoven, and Steve Vai (for those who haven't had the good fortune to come across him, he is an incredibly talented instrumental rock guitarist).

Here is a quote from Dr Leigh Riby, who, along with George Caldwell (both cognitive psychologists at Glasgow Caledonian University) performed the study:

What we found was surprising. While classical music appears to have an effect on everybody, we also found that there is a significant effect on people exposed to their favourite type of music.

The study results were published in the current edition of Consciousness and Cognition, the science journal. You can read a newspaper write-up here.

Hear the Sun Sing

Standford University has an interesting site on the Internet regarding helioseismology, which is the study of the Sun using sound (pressure) waves. To accomplish this, images are captured of the Sun's surface; the movements of the surface are extracted and converted to audio signals; and, finally, the signals are filtered and analyzed to determine things about the internal structure and dynamics of the Sun. One neat thing that comes out of it is that you can listen to the filtered audio signals - a technologically derived "music of the spheres". It takes the poetry out of the whole process but it can still be beautiful in its own (geeky) way.

This humorous quote caught my eye:

So, like seismologists who study earthquakes, helioseismologists study "quakes" on the sun. Their job is a bit like figuring out how a piano was put together by listening to it fall down the stairs!

The site is by the Stanford Solar Center; information and audio files can be found here.

(Hat tip: ICAD mailing list, run by the International Conference on Auditory Display)

Effects of 9/11 on small technical-security businesses

This article basically gets it right judging by what I have seen - in short, if you were not providing computers, communications, or x-ray screening products, then you didn't see much in the way of increased purchases of tech-sec products after 9/11, at least in the USA.

I believe that I can actually generalize even further based on my (admittedly unscientific) polling of tech-sec product companies by saying that 9/11 vacuumed up budgets to pay for extra personnel-related charges (e.g. overtime pay) and to procure screening equipment (e.g. the aforementioned x-ray machines). The confusion that resulted from merging lots of componets into the new DHS (Department of Homeland Security) further locked up RD&E as well as Production procurement budgets, most of which have not returned to pre-9/11 levels for the many small businesses across the USA. Finally, the major security-defense contractors got big integration contracts, which pulled even more money from small tech-sec businesses.

So, contrary to popular belief, the last few years were not kind to small businesses in this field. The good news for them is that it looks like this situation is changing.

(Author's note: edited for clarity after initial post - blogging on too little sleep!)

Specialy careers in forensics

Here is a link to a short article in the Lousiville (Kentucky) Courier-Journal on forensic careers in state and local law enforcement organizations. Here are the high-points of the article:

The Louisville Metro Police Department employs about a dozen forensic experts in its Evidence Technician Squad, Computer Forensics and Analysis Squad, and Video Forensics and Analysis Squad.

The average annual salary for the department's evidence technicians is about $39,700, said Officer Dwight Mitchell, a Louisville Metro Police spokesman.

Forensic experts are also employed by the state of Kentucky with salaries ranging from about $75,000 for a forensic scientist specialist to about $175,000 for a chief medical examiner.

Using video technology to assist with tunnel vision

Tunnel vision is a debilitating side-effect for some sufferers of glaucoma and RP (retinitis pigmentosa). Scientists at the Schepens Eye Research Institute, an affiliate of Harvard Medical School, have been trying to help these sufferers by overlaying processed video images on top of what would normally be seen. The device they have invented consists of a miniature camera, pocket-sized computer and transparent computer display mounted on a pair of eye glasses (see image above). The video is rendered at 30 frames a second to provide full-motion images. The processed image that is overlayed is a wider field-of-view image that only shows outlines of objects (obtained by filtering with an edge-detection algorithm)(see image below).

To view a video (avi or mov) follow this link to the Harvard web site. The Schepens press release is here.

(Hat-tip: Science Daily)
(Image sources: Graham Ramsey photo on Schepens web site and Science Daily)

Additional sources of audio and video evidence

I came across this news article today that illustrates one of the other sources of audio and video evidence used in legal proceedings. In this case the source was from recordings made during the interview of a suspect (now defendent) and it was introduced into his trial to help establish his state of mind - in other words, whether he was "legally insane" at the time of the murder.

As you can now see, audio and video evidence is not only obtained from surveillance or recovery (e.g. from the scene of the crime, nearby ATM cameras, etc.). As a matter of fact, in recent years recording of police interviews has become increasingly common throughout the world, so this source of audio and video evidence will also become more common in trials.

Age related hearing loss may also have hereditary component

The BBC reports on work funded by the Royal National Institute for Deaf People:

About 37% of Britons aged 61 to 70 and 60% of those aged 71 to 80 - 6.5m people - have age-related hearing loss.

The Human Mutation study of over 1,200 people found subtle changes in a gene called KCNQ4 were more common in those with age-related hearing problems.

Based on this study, common age related hearing loss appears likely to be due to a combination of environmental (e.g. exposure to loud sounds) and genetic factors. The gene KCNQ4 has previously been linked to a hereditary form of hearing loss that strikes young people, regardless of exposure to loud sounds. This doesn't mean that exposure to loud sounds won't cause hearing loss - it will. Instead, the way I interpret the study, it is more likely that if KCNQ4 is seriously defective then hearing loss strikes early; if it is a defective to a "lesser" extent, then one is more succeptible to age related hearing loss; and, finally, if it is normal, one can still lose hearing due to loud sounds (and maybe through other mechanisms, such as age related degradation of tissues and such in the ear).

Note: The above is my own interpretation and is meant to estimate a trend, based on experience and scientific reasoning, and may not be fully supported by existing data.

Air traffic control intercepts of Northwest Airlines turnback flight with F-16 escort

Audio recordings (wma format) of conversations between air traffic control and the F-16 escort for Northwest Airlines flight 42 to Mumbai that had to turn back to Schiphol (Netherlands) due to concerns about some passengers. Recordings courtesy of the Frequency Monitoring Centre, the Netherlands. Recording is very intelligible with only a little hiss and occassional louder noise.

(Hat tip: Flight Global) (note: I stumbled across the Flight Global page from a news article but now can't find the original site that got me on the trail).

Naps enable additional learning in babies

ScienceDaily reports that psychologists at the University of Arizona have found that naps enabled babies to learn more than ones who didn't take naps. Sleep has been long known to cement memory formation in adults. This sounds like the beginnings of a good excuse for that Sunday nap - "But honey, scientists have shown that it will make me smarter and improve my memory!"

The study was published in the August issue of Psychological Science.

(Hat tip: ScienceDaily)

Exhibits from trial of Zacarias Moussaoui

Trial exhibits from prosecution and defense of Zacarias Moussaoui are now available online here. Security camera photos, video clips, emails, transcripts, money transfers, faxes, receipts, and audio clips (just to name a few!) are included. If you want to see how a major terrorist case is assembled, this is a good place to start.

(Hat tip: Chronicles of Max)

The last two months were not kind...

William (Bill) K. Heineman -Washington Post obituary
Bill made important contributions to law enforcement and security over the years, both in government service (FBI) and in industry (Tektron). He was respected, admired, and appreciated by many for his accomplishments as well as his character.

Steven C. Marshall (a.k.a. Stephen St. Croix) - Forbes obituary. (Updated: Mix magazine obituary)
Few people leave a mark in a single industry - Stephen left marks in three different industries - in the movies (Star Wars, Wizard of Oz, and Gone with the Wind), in music (Songs in the Key of Life), and in law enforcement (Intelligent Devices).

Both of them were called from us early and will be missed.

New links and other housekeeping

Finally managed to get around to some housekeeping duties tonight - corrected links to pages that had moved as well as added some new links in the Science, Security, Biometrics, and Politics sections (on the right hand side).

Study to ID a person by texting style

Researchers at the University of Leicester (UK) are undertaking a study to determine if it might be possible to recognize an individual by their texting style. The psychologists involved plan to use linguistic analysis on text submitted by volunteers who will participate over the Internet.

(Hat tip: CNET.CO.UK)

Security camera deployment and operational issues in the USA

Some time ago I posted about the 'evils' of highly compressing security camera images in order to maximize the number of days of footage that could be stored. That post came to mind as I read an article in the Washington Times online edition that talked about camers to be installed in WDC and referenced similar programs in Baltimore, Chicago, and San Francisco. The first quote that caught my eye was about statistics collected from the Baltimore system and it said:

"Generally, the State's Attorney's Office has not found them to be a useful tool to prosecutors," office spokeswoman Margaret Burns said. "They're good for circumstantial evidence, but it definitely isn't evidence we find useful to convict somebody of a crime."

That quote was followed by this one:

"We have not used any footage to resolve a violent-crime case," she said.
Miss Burns said police sometimes misidentify suspects because the cameras produce "grainy" and "blurry" images.
"We have had that happen more than once," she said.

"Why?", you might ask. The things that come immediately to mind are 1) too far away, 2) poor lighting, 3) poor lens/camera, and 4) too much compression. I'd be willing to wager money on it being the latter, at least in large part. I say that based on experience and also on noting what wasn't said - no complaints about live monitoring - as well as an inference I made based on the fact that a security camera helped solve one case even though no image was recorded (which to me says that an operator likely saw something important using the camera).

The entire article is interesting and gives some insight into real-life issues with deploying and operating these systems. Many of these issues are addressable and data like this can help point the way to workable solutions.

Predictors of late talking in toddlers

Science Daily has an article (13 July 2006) on a study by the Telethon Institute for Child Health Research, Curtin University of Technology, and the University of Kansas (USA) on predictors of late talking in toddlers.

The main findings of the study were that 1) roughly 13 percent of children at age two were late talkers; 2) that factors involving mothers' education, income, and such had no significant influence; and 3) that most late talkers had normal language development by age seven.

To read more, see Telethon Institute for Child Health Research.

Hiatus comes to an end

After an array processing conference (SAM 2006, short for Sensor Array and Multi-channel processing), one international business trip, one law enforcement conference (NATIA 2006, where I was a speaker), and a patent filing, I am finally back to blogging. It was a busy few weeks...

Hearing words activates brain's speech center even before learning to talk

Science Daily has a report on a study on the relationship between hearing and speaking in infants.

Note: My posts will continue to be brief for about another two weeks.

Non-lethal sonic blasters for US National Guard troops

DefenseTech reports on the Pentagon's plans for deploying sonic blasters and other non-lethal devices with National Guard troops.

Posting will be light

Posting will be light for a couple of weeks due to work committments. If you are new to this blog, I encourage you to try the archives (see the right hand sidebar toward the bottom).

Biometric ID cards for personnel at US federal agencies

Security Document World reports on the initial steps in implementing Homeland Security Presidential Directive (HSPD) 12, which requires US federal agencies to issue biometric-based smart ID cards to all new employees and contractors by October 27, 2006.

Stroke victim wakes up with new accent

The Telegraph newspaper (UK) reports today that upon after emerging from a stroke a woman's Geordie accent had been replaced by a Jamaican one. Her condition, called the foreign accent syndrome, is a rare occurrence - there have been only about 50 recorded cases.

Best time for cochlea implants in children

ScienceDaily reports on a study by Johanna Grant Nicholas, Ph.D., research associate professor of otolaryngology at Washington University School of Medicine in St. Louis and colleague Ann E. Geers, Ph.D., from the Southwestern Medical School at the University of Texas at Dallas into determining the best age for a deaf child to receive a cochlea implant. The study found that the answer is before 24 months old if the goal is to have the child speak at the same level as other hearing peers. The National Institute of Deafness and Other Communication Disorders supported this research with funding.

Mapping where the brain processes tones

Researchers at the Max Planck Institute for Biological Cybernetics in Tübingen have published a paper (PLoS Biology, June 20, 2006) on the results of their fMRI study into mapping where the human brain processes tones and tone combinations. ScienceDaily has a good write-up on the paper for those with a basic technical understanding of how the auditory system works.

The study seems to have produced a more detailed understanding of the mapping between the cochlea and the Auditory Cortex Fields (ACF) of the brain, where the processing (is it separation and/or decoding?) of tones takes place, as well as the organization of the ACFs.

(Hat tip: ScienceDaily)

Shoeveillance

Marc Böhlen of Real Tech Support has an interesting take on surveilling people in a building - instead of mounting surveillance cameras up high and watching faces, he mounts them down low and images feet and shoes instead. The idea is to have a surveillance system for automatic people counting and safety that is less invasive of people's privacy. For example, security personnel could use it to know if there are any people in a particular area of a building in case of emergency.

As a concept, I think it is intriguing. Thinking about it from a systems perspective, however, the efficiency of emergency response would be improved by knowing what a person (not just their shoes) looked like as well as being able to more thoroughly surveil the area. Putting both systems side-by-side would allow one to leave the more invasive system inactive until needed, but that would be more expensive. What it seems to come down to is a classic tradeoff between privacy, security, and cost.

A link to his site is here.

Links between motor skills and language development in children

A recent study has (again) found a link between motor skills and language development. From the press release:

Youngsters who can lick their lips, blow bubbles and pretend that a building block is a car are most likely to find learning language easy, according to a new study funded by the Economic and Social Research Council (ESRC). Psychologists at Lancaster University, led by Dr Katie Alcock, found strong links between these movement, or motor and thinking, or cognitive, skills and children's language abilities.

Speech therapists and pediatricians have known about a link between motor skills and language for some time. In fact, speech therapists use motor skill development games (e.g. the game with the small fish that move around and the minature fishing pole with a magnetic 'hook') in their sessions with children for that reason. It appears to me that the unique bit in this study is probably the correlation between the specific motor skills involving the mouth (i.e. blowing bubbles) and speaking. This make intuitive sense, of course.

So, this is indeed a study result that children can be happy about - chewing bubble gum is good for development!

(Hat tip: ScienceDaily)

PS. As a general point, please remember that finding a link is not the same thing as finding causality. In other words, two things can be related but not caused by each other but instead by something completely different. Statistically discovered "links" can also be due to coincidence if the study is not constructed carefully. More study is usually needed to reach the point where cause and effect are understood.

Computerized Voice Stress Analysis

The subject of Computerized Voice Stress Analysis (CVSA) has been brought up to me several times in the last month or so. Here is an article that sums up the issues in a non-technical way fairly well.

For the record, I believe that the prevailing opinion in the community is that CVSA should be viewed as an interrogation aid and not a lie-detector. Detecting if someone has micro-tremors in their speech pattern is not the same as detecting deception. Police departments should understand that it may be relatively inexpensive and simple to administer but it is no more reliable than the bit of folk lore about cops using a copy machine and letting the suspect believe that it was a lie detector.

Please don't put that hard disk in the bulk tape eraser

Scientists at the Georgia Tech Research Institute (USA) have been busy with a project for the military that may have future application to audio and video surveillance and forensics by law enforcement. It addresses the problem of not having a universal eraser for all magnetic media.

With the explosion of new types of digital recording devices and storage media, equipment and procedures for reliably and efficiently erasing the media will likely become a pressing issue. The community has been through this before though. When digital audio tape (DAT) came out, quite a few professionals made the mistake of thinking that their old bulk (analog) tape erasers would wipe them clean, but the magnetic fields used for analog tape eraser were not strong enough for digital tape.

ScienceDaily link is here.

Battlefield acoustics

I haven't blogged about sound on the battlefield yet, so this new StrategyPage article is as good a one to start with as I could hope for.

This produces another unique battlefield sound portrait. You know American troops are at work when one shell goes off, followed by a few shots. No shouting, American troops use individual radios, hand signals and night vision equipment. They move fast, using minimal firepower. Less risk of friendly fire, or collateral damage (civilian casualties or property damage.) Battlefields have never sounded like this.

Pluto's Newest Moons Named Hydra and Nix

Space.com has the details.

Off-topic post: Viewing USPTO patent images

Unless you either browse US patents or write US patent applications, this probably is not of interest to you and I apologize for this off-topic posting.

The reason I am posting it is that for those of us who do use the USPTO (US Patent and Trademark Office) website, one of the big frustrations most everyone has is the inability to view the patent images. For technical reasons, Apple Quicktime tries to load the TIFF images of the patents and drawings, but cannot do it correctly (so you get none or only part of the image). Like most people who have not discovered "the secret" (after having similarly failed with all the other advertised plug-ins and such), I adopted a work-around using a free patent server, but this was awkward.

Anyway, to make a long story shorter, I have found an image viewer that works in Firefox and IE - Alternatiff. Here is the link. I hope it saves you the frustration I've experienced over the last several years.

Digital camera neutralizing technique

There have been been devices on the market that detect lenses for some time , but a system was recently prototyped that is, to my knowledge, the first that goes beyond simple detection and actively counters the operation of at least some digital camera systems.

(Disclosure: my company markets a Russian-manufactured device that detects optics.)

Engineers at the Georgia Institute of Technology have prototyped a system to automatically detect and temporarily blind the image sensors used in digital cameras. Detection is accomplished by exploiting a characteristic of digital image sensors - by their nature, they reflect light back to the source (i.e. retroreflection).

Automatically finding reflections isn't all that difficult, but then you have to filter out the false positives (reflections which aren't really from camera sensors) and guide beams of light at the remaining reflectors. This article describes some general details of the method.

Proposed uses include thwarting people making pirated videos in cinemas, paedophiles making videos of children visiting shopping mall Santas, espionage in government buildings, and so on. The technique will not work against still image cameras that use a shutter to shield the sensor until a picture is taken, which includes some digital cameras and all film cameras.

(Hat tip: Digg)

Video filtering intersects with art

What do you get when you mash up an optical flow algorithm, a spotlight, and a museum?

ACCESS, which is an

art installation where a computer-controlled spotlight would track and follow unsuspecting persons in a public space.

See TechEBlog for video with audio description.

(Hat tip: Digg)

Video of meteoroid hitting the Moon

NASA (the US National Aeronautics and Space Administration) has posted a video of a meteoroid hitting the Moon. Link for article and video download is here.

(Hat tip: Digg)

Patents for identifying a digital camera by its noise signature

Photonics.com has an article on two patent applications related to a technique to identify which digital camera took a particular photograph. The inventors are researchers at State University of New York at Binghamton (NY, USA). The lead researcher is Jessica Fridrich.

The general idea of identifying digital cameras by their 'dead' (i.e. non-functioning) pixels or other characteristics of their image sensor has been discussed over the past few years and some techniques have emerged to identify brands of cameras (due to their manufacturers' standard implementation of internal image processing and such) and even individual cameras.

The new technique described in the article is based on extracting a very weak noise pattern that is present in all digital photographic images due to inhomogeneities in solid-state sensors used. The inventors claim that their technique can extract this pattern from a single image. Since it is based on a pattern derived from the several million pixels present in most current digital cameras, they intuit that it may indeed be unique. This is a claim that has to be made very, very carefully. With scientific (in this case, forensic) analysis that may be used in court, it is especially important to not claim that a signature is "unique" until it can be proven to an accepted legal standard, such as Daubert in the USA.

Test your high frequency hearing

I've started this as a new post, even though it really is a spin-off of this previous post. Here is a link to test your high frequency hearing.

(Hat tip: GeekPress)

Much more impressive than "Polly wants a cracker"

I've watched (and listened to) the entire video and still can hardly believe it - I mean really, a bird mimicking a chain saw and a motor-driven camera?

(Hat tip: Digg)

Surprising study of American hearing

LiveSience reports on work presented at the spring meeting of the Acoustical Society of America that compares the hearing of a broad cross-section of Americans over time. What was surprising is that despite technical and economic factors during the last 35 years (think boom boxes, growth in construction and its associated noise, explosion in jet travel, etc.), the hearing of the average American is about the same instead of significantly worse. For completeness, I should also note that women's hearing was better than men's, but that shouldn't be surprising (shooting ranges, motorbikes, and movies with lots of explosions immediately come to mind as possible explanations for that!).

For the LiveScience report, click here.

fMRI finds other functions of Broca's area of brain

Functional magnetic resonance imaging ( fMRI) has reportedly yielded another insight into how the human brain functions. fMRI is a non-invasive imaging technique that exploits a particular modern instrument's ability to sense the magnetic properties of water in order to detect changes in the rate that tissue is using oxygen. How rapidly a tissue uses oxygen is a good indicator of how much work it is doing. So, when using fMRI to study a human doing mental tasks, a scientist can tell which areas of the brain are active (functioning).

Using the fMRI technique in a controlled study, French researchers at Université Pierre et Marie Curie and Ecole Normale Supérieure have reportedly discovered that Broca's area (located near the left temple), along with its companion area on the right side, is involved in more than just organizing speech - it also organizes (plans) many other things. This planning ability is one of the major things that distinguishes human intelligence from that of other species.

For more on the study, click here.

(Hat tip: Digg)

Device allows legally blind to see

A poet at MIT (Massachusetts Institute of Technology, USA) has developed a machine that allows legally blind people who have at least some healthy retina left to see images that the machine projects and focuses in their eyes. It has been tested on at least 10 legally blind people with good results.

An analogy would be a hearing aid for (partially) deaf people. A partially deaf person's hearing does respond to sound but in many cases it requires significant amplification first, which is what the hearing aid does. In this visual system, the machine provides amplification and focusing of light instead. Pretty neat! Maybe this has been done before since it seems to be a pretty obvious solution to the problem, but if it hasn't, then the lead designer (Elizabeth Goldring, a senior fellow at MIT's Center for Advanced Visual Studies) deserves even more credit.

Here is a link to the MIT press office write-up.

Sounds on Mars

This week's Physics News update email brought to my attention some acoustics research presented at the yearly conference of one of my professional societies, the Acoustical Society of America. The work was performed by researchers from Penn State University (USA) and is about simulating how sound travels on the planet Mars. Here is an excerpt:

... detailed computer calculations that simulate how sound travels through the Martian atmosphere, which is much thinner than Earth's (exerting only 0.7% of the pressure of our atmosphere on the surface) and has a very different composition (containing 95.3% carbon dioxide, compared to about 0.33% on our planet). The loss of 1999's Mars Polar Lander, which was to record sounds directly on the planet, has compelled researchers to find other means to study how sound travels there.

This is a technical piece of work, but if you have a science background of any type it should be clearly understandable. For those who are into this type of thing, the simulation algorithm used was Direct Simulation Monte-Carlo. An overview of the paper in layman's language is available at the Acoustical Society's website. It also includes a link to a video (which unfortunately I haven't been able to get to play yet due to some codec error) (UPDATE: they have fixed the problem)

Recent history of imaging

There is a nice summary of the recent history of imaging on the Advanced Imaging Pro website. The article covers many branches of imaging, including a small bit about law enforcement.

Recovered evidence is different

A news report in The Examiner (Eastern Jackson County, Missouri, USA - registration may be required) brought to mind the differences in 'recovered' versus 'surveillance' evidence. In this specific case the authorities have arrested and arraigned a couple on charges related to three victims who were variously kidnapped, sexually molested, assaulted and murdered. Allegedly, two adult female victims were murdered and one female child victim was kidnapped and assaulted. According to the newspaper account, the forensic evidence includes:

... an address book that contained references to "choking," "chasing" and "sexual desires." Other evidence includes duct tape with hair; a video camera; and a videotape of Spicer being sexually assaulted and beaten.

Sanders said more than 20 videotapes and some audio tapes, including at least one 90-minute tape, were found in the truck Davis, 41, and Riley, 39, crashed in Barton County, near Lamar, Mo., last week. They were found by Barton County Sheriff's officers. Police also found videotapes where Davis worked. The tapes are similar to the one found at Davis' apartment and show Spicer and Ricci being abused.

I don't know anything more about this case than what I read in the article, but the point I want to make is a general one about the challenges of performing audio and video forensics on evidence that is recovered by a crime scene investigation.

When a technical surveillance unit (TSU) collects audio and/or video, by and large, the forensic examiner can reasonably expect that any media received for examination will have been recorded using standard equipment and procedures, as well as the fact that most, if not all, of it will be relevant.

Note: This does vary, of course, due to skills, training, equipment maintenance, equipment budgets, and operational constraints (e.g. time and opportunity). Just because it was recorded by a tech surveillance unit doesn't mean that it will be perfect; however, the odds that it will be useable are improved substantially.

Not so with recovered evidence - who knows when the last time the tapes in the answering machine found at the crime scene were changed? Probably not in the last two years, Murphy's Law says! Was an external or internal mic used on the video camcorder? Yeah, right. Was the lens clean on the camera? Was the right lens used for the lighting and distance involved? Was the audio and/or video over-compressed? Were the batteries freshly charged? Did he (i.e. the suspect) try to perserve the evidence or destroy it? Did the "black box" come through the crash unscathed? The list goes on and on...

The long and short of it is that recovered audio/video evidence is like a grab bag at a tourist trap - you never know what you are going to get, but you can pretty much expect that it won't thrill you. And in cases such as (videotaped) sexual assault and murder, it can be as, or even more, grim than what the classic 'wet' forensic disciplines deal with (e.g. blood, semen, autopsies). In the context of this post, recovered evidence is the most challenging type that an audio/video examiner can receive, by far.

SASER - the sound analog of LASER

What do you get when you cross acoustics and lasers? The answer is a SASER (Sound Amplification by Stimulated Emission of Radiation). This has been done before but there is a new implementation out. Work was by University of Nottingham in the UK and the Lashkarev Institute of Semiconductor Physics in the Ukraine and is in the 2 June 2006 edition of Physical Review Letter.

(Hat tip: Physics News Update)

Forensic Linguistics PhD scholarship opportunity

I'm passing along this advance notice.

The University of Aston will shortly, (hopefully by mid-June), be inviting applications for a three year PhD scholarship in the areas of Forensic Linguistics and Language and the Law, in memory of Phill Newbury. The scholarship will be available from October 1st and will be worth a little over £15,000 a year. For a student resident in the European Union, this will be sufficient to pay the full university fees, plus a maintenance allowance of £12,000. Non-EU students are also welcome to apply, but sadly the maintenance allowance will be lower as the university fees, at some £8,750, are considerably higher.

Commercial loudspeaker array

I recently blogged about microphone array support coming to Windows Vista. Now, here is an array implemented on the other end of the audio chain - not for capture but instead for rendering - Pioneer's surround sound loudspeaker array. The press release bills the PDSP-1 as "the world's first digital sound projector." "Why use an array?", you may ask. The answer is that one loudspeaker array can project multiple beams of sound - in this case the separate channels for 5.1 surround sound - thereby eliminating the need to mount and wire multiple surround sound speakers in your multimedia room.

(Hat tip and image source: SciFi.com)

Audio recordings help prevent bombing of Ministry of Sound

From an article in the UK's Guardian newspaper:

An alleged British terror cell talked of blowing up London's Ministry of Sound nightclub, the Old Bailey heard today.

Jurors were played secret security service recordings in which two members of the alleged cell discussed possible terror targets in the capital and across England.

Jawad Akbar and Omar Khyam, both members of the group - which was allegedly linked to al-Qaida - considered the Ministry of Sound, which can hold up to 1,800 people, to be an easy target.

(Hat tip: Winds of Change)

Teens exploit presbycusis (age-related hearing loss)

Techno-savvy schoolkids in the west of Britain (Wales, to be specific) have inventively adapted a security technology to their own purposes. The Mosquito technology was developed by a UK firm to use high frequency sounds to drive young gangs away from shopping centers. Once people are over about 20 years old, their hearing is no longer very sensitive to the upper audio frequencies - a natural condition known as presbycusis, or age-related hearing loss. So the security concept goes, play loud, annoying sounds in the 18-20 kHz range and kids will move away (and dogs!) while adults will be not be bothered unless they are so close to the sound source to make it loud enough to overcome their loss of sensitivity.

So, that brings us to the teenagers' exploit - record the Mosquito tones (clever marketing name, that) and use them as ringtones on their mobile phones. Now they are able to get text message and call alerts during class without their teachers hearing them! News article here.

(Hat tip: GeekPress).

Zapruder film discrepencies?

Ok, straight off, I'm not a conspiracy theorist so I'm not sure I should be posting this at all, but the source is a respectable MSM news magazine.

US News & World Report has a couple of short pieces (one and two) about possible tampering involving the Zapruder film of the assassination of JFK. Links to scanned images are on the second of the two pages. Comparison of the images allegedly show discrepencies in the color of shoes, which is why I thought this might be of professional interest. Please note that I have not studied these in detail and am not supporting or refuting any allegations.

(Image Source: US News & World Report)

Cool Salt video - visual demonstration of standing waves

There is a video called Cool Salt making the rounds of the Internet science blogs (WARNING: turn the volume on your speakers or headphones down before you play the video. Some of the frequencies will hurt your ears if you don't).

What the video shows are the standing wave patterns produced by exciting an elastic sheet with salt on it using an audio tone generator. The tone generator is then tuned through audible frequencies, pausing at obvious resonant frequencies of the sheet (i.e. frequencies where it produces standing waves determined by the dimensions of the sheet). The salt settles into patterns that help you to visualize the standing waves set up at the resonant frequencies. I read one blog comment by a competent-seeming person that said that the salt settles to the points where the sheet is not displaced at all, but that doesn't sound quite right to me. Maybe I'm missing something, but it seems to me that the salt should settle to the lowest points of the standing wave, which would be a regular pattern of sationary dips. I'll have to give this some more thought (or, even better, just do the experiment in my next lecture on audio). If any of you readers have any additional insight, please post a comment!

This type of demonstration is a classic one used in high school and university physics classes around the world. The study of these patterns can be traced back to Ernst Chladni (a modern founder of the science of acoustics) and his student Hans Jenny, who popularized the study of such patterns in his 1967 book Cymatics (from the Greek word "kyma" meaning "waves"). "Cymatics" is now the recognized term for the study of wave phenomena.

(Hat tip: Digg)
(Image Source: a Chladni figure found in the Wiki entry on Cymatics)

Former police audio engineer applies skills to Da Vinci Code voices

What our voices sound like depends on a lot of factors - vocal tract length, coarseness of vocal cords (which is in turn influenced by testosterone levels, smoking, etc.), and shape of the jaw, just to name a few. One former police audio engineer, Matsumi Suzuki, of the Japan Acoustic Lab in Tokyo has reconstructed the voices of Da Vinci and Mona Lisa for commercial purposes. The reconstructed voices are being used as part of the promotional efforts for the recent movie, The Da Vinci Code, which, in case you've been temporarily disconnected from mainstream media for the last year or more, is based on an artsy-religious-historical-thriller book by Dan Brown.

Personal aside: As I've been a Freemason for many years and am also keen on history and religion, I really am amazed at the amount of interest in 'The Da Vinci Code' and 'Angels and Demons'. I hopeful that these bits of pop-fluff entertainment will entice more people of all persuasions into studying more about our past (and judging by the number of books in the local bookshops on all aspects of 'The Code', somebody must be). It is my fervent belief that we have a lot to learn from our ancestors. They were people just like us in their struggles, hopes, and dreams but probably a good bit smarter and wiser since they actually used their senses and brains for analyzing things, both small and large.

I originally got onto this topic via this article on PhysOrg but after some digging around trying to find an actual link to the Japan Acoustic Lab webpage (which I didn't ever find) I came across a more comprehensive write-up on the origins of the Da Vinci and Mona Lisa reconstructions. It turns out that the lab was reconstructing various famous voices that are now sold as ringtones for mobile phones.

As far as forensic science goes, I was pleased to see that many of the articles I found on the Internet about the reconstructions did point out that there were a lot of assumptions that had to be made, including Mona Lisa's height for starters as she is sitting down in her portrait.

(Image source: J@pan Inc. website)

How about downloading some legal free music?

The University of California Santa Barbara has been experiencing a rash of ripping and downloading - but unlike many universities it isn't worried because this isn't the illegal type. The Cylinder Preservation and Digitization Project at UCSB has taken 6000 cylinder recordings and made them available online as individual downloads and an internet radio stream. Because of their inspired efforts, you can listen to historical figures, such as Theodore Roosevelt and Ernest Shackleton, as well as comedy routines, church choirs, arias, the Orchestra of Afghanastan, and many more important, beautiful, and eclectic recordings made between 1875 and 1929.

It is surprisingly refreshing and addictive. Give it a listen and hear for yourself.

(Hat tip: Daily Telegraph)
(Image source: UCSB Cylinder Preservation and Digitization Project)

DIY Camera Obscura

In way of background for this post, I should explain that a camera obscura is a dark box (or room) with a hole in to that allows an image from outside to be projected into the camera (meaning, in the original sense, a "box"). The image is upside-down due to the pinhole lens effect. Also, the larger you make the hole the brighter but more fuzzy the image is. The camera obscura was the forerunner of both cinema and film cameras. Special rooms were constructed to allow paying audiences to view these projections as a form of entertainment.

With that background, I offer a link to a DIY camera obscura. This is a great project that improves on the original variety by incorporating a modern lens to allow bright AND sharp(er) images at the same time. I'm planning on making one of these with my kids during the summer holidays so they can view the morning sunrise in an interesting way.

(Hat tip: Make)

Small world image contest

Nikon has been running a contest since 1973 for images captured from microscopes. Here is a gallery of this past year's winners along with a few particularly striking ones from previous years. Technically cool and artistic as well. Enjoy!

(Image source: Nikon Small World Gallery)

Light posting coming to an end

Posting has been light these last two weeks due to work-related travel. On the plus side, I got to attend the SPIE Defense and Security Symposium in Orlando, Florida, USA. Lots of good optics kit on exhibit, along with some very good presentations on the technical side.

Microphone array support coming with Windows Vista

Microphone array beamforming is a subject that I have given a lot of my attention to over the last ten years or so. Simply put, microphone arrays are the electronic equivalent of a parabolic dish (those big plexiglass dishes that they use at football games to hear the sounds of contact and shouted calls on the field). Mic arrays let you hear sounds in a particular direction, possibly even far away, depending on the system design and environmental conditions.

As you might guess, I was pleased to learn last year that Microsoft will be building support for small arrays into Vista, its next generation version of Windows. The idea is that laptop and tablet PC manufacturers will embed small (4 element) mic arrays into their products to focus on the user's voice and cut down on noise so that VOIP, speech recognition, and other voice-based applications can work better. They also included an automatic echo canceller (AEC) to kill feedback loops between the microphone and loudspeaker in the laptop or tablet PC. These feedback loops are familiar to all who remember assemblies in gradeschool when the principal got his microphone too close to the loudspeaker and everyone got an earful of a high-pitched screeching tone! This would also happen on a VOIP call if the AEC wasn't included, so that is a good thing.

Anyway, I came across a introductory video clip from Microsoft Research on the topic of mic arrays and what is coming out in Vista. It can be found here. Note for Firefox users: you may need to use "Open in IE Tab" for the plug-in to play the video correctly.

(Image source: Microsoft Research - a four element, uniformly spaced, linear microphone array with USB cable)