Wednesday, December 06, 2006
Friday, December 01, 2006
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.
Tuesday, November 21, 2006
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!
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.
(Hat tip: Eyewitness News 24 and CW30)
Thursday, November 16, 2006
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.
Tuesday, November 14, 2006
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)
Monday, November 13, 2006
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).
Sunday, November 12, 2006
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)
Thursday, November 09, 2006
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.)
Experience suggests that one or more of the following common occurrences could have happened:
- the record head was out of alignment, dirty, or magnetized;
- 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);
- 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);
- that the tape had not been changed recently (if their policy was to reuse tapes);
- there was an electrical power grounding problem (causing hum);
- the recorder had some other fault (bad tensioner maybe, but then the video would have been out of sync also); or
- the suspect was too far from the microphone to pick up clearly (doesn't sound like the case here though).
Wednesday, November 08, 2006
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.
Monday, November 06, 2006
Research Assistant/fellow (2 posts), Eyewitness Memory, University of Aberdeen (UK)
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
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)
The successful candidate will teach 12 hours per semester in the Criminal Justice and Criminology Department. Closing date: 7 Jan 2007
Sunday, November 05, 2006
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.
Friday, October 27, 2006
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
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.
... 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.
Sunday, October 22, 2006
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.
UPDATE: WAVE online report with significantly more info.
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.
Monday, October 09, 2006
(Hat tip: scenta musci and news)
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.
Saturday, September 30, 2006
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))
Thursday, September 21, 2006
Sigh... and I had to be on business travel (again)...
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)
On an audio/video recording broadcast on TV, the defendent says in Arabic that:
The defendent's words speak for themselves.
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".
Tuesday, September 05, 2006
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.
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.
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)
Monday, September 04, 2006
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!)
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.
Saturday, September 02, 2006
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)
Sunday, August 27, 2006
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.
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.
Saturday, August 26, 2006
(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).
Wednesday, August 16, 2006
The study was published in the August issue of Psychological Science.
(Hat tip: ScienceDaily)
Tuesday, August 15, 2006
(Hat tip: Chronicles of Max)
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.
(Hat tip: CNET.CO.UK)
"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.
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.
Sunday, July 16, 2006
Note: My posts will continue to be brief for about another two weeks.
Tuesday, July 11, 2006
Thursday, July 06, 2006
Tuesday, July 04, 2006
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)
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.
Sunday, July 02, 2006
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.
Saturday, July 01, 2006
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.
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.
Saturday, June 24, 2006
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.
Friday, June 23, 2006
Thursday, June 22, 2006
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.
Monday, June 19, 2006
(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)
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)
Friday, June 16, 2006
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.
Thursday, June 15, 2006
For the LiveScience report, click here.
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)
Saturday, June 10, 2006
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.
... 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)
Friday, June 09, 2006
Monday, June 05, 2006
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.
... 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.
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.
Friday, June 02, 2006
(Hat tip: Physics News Update)
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.
Tuesday, May 30, 2006
(Hat tip and image source: SciFi.com)
Sunday, May 28, 2006
An alleged British terror cell talked of blowing up London's Ministry of Sound nightclub, the Old Bailey heard today.(Hat tip: Winds of Change)
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.
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).
Friday, May 26, 2006
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)
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)
Monday, May 22, 2006
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)
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)
Monday, May 08, 2006
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)
Monday, May 01, 2006
(Image source: Nikon Small World Gallery)
Friday, April 28, 2006
Saturday, April 08, 2006
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)