Wednesday, December 31, 2008
(Hat tip to Forensic Focus)
Wednesday, December 24, 2008
One of the podcasts I enjoy on a frequent basis is All in the Mind, by ABC Radio National (Australia). Last week's episode was titled "Untangling Tricky Talk" and covered forensic linguistics as well as transcription by deaf people. The forensic linguistic portion was centered around an interview of Paul Foulkes, who gave a very professional account of his discipline.
Tuesday, December 23, 2008
Of course, susceptibility to tampering is not the only thing to be considered when evaluating the relative merits of digital imagery as evidence, but it is obvious that tampering with a digital copy is easier to do and (possibly) get away with than tampering with film or tape.
Farid first conceived of the possibilities of digital forensics while at MIT, waiting in the checkout line at the library. Restless, he picked up a copy of the Federal Rules of Evidence, then started randomly reading. What he saw startled him: Film and digital images were equivalent evidence, in the eyes of the court.
"This just seemed like a bad idea,'' he said. "Not that I'm good at seeing the future — but I could tell this would be a problem."
Sunday, December 14, 2008
If any of you readers did see the episode and would like to fill us in, please do!
Tuesday, December 02, 2008
These devices work by emitting an RF (radio frequency) radar pulse, listening for the reflection of that pulse off of objects in the wall and on the other side, and using time-delay (i.e. how long it takes for the reflected pulse to come back) and direction (i.e. which direction did the reflection come from) information to construct a picture. This is similar to how bats and dolphins use acoustic echo location, just with an RF pulse instead of sound pulses.
This is a handy capability to have in hostage and other situations where a team has to enter a building where armed attackers or booby traps might be waiting for them. The engineering problems that had to be solved in order to come up with a deployable system were extremely challenging - my had is off to the teams that did this.
PS. In case you are interested, I posted some time ago about a DARPA (Defense Advanced Research Projects Agency, US Department of Defense) effort that developed a through-wall motion detector which was compact and lightweight - so light-weight that you use it with a single hand, like a stud-finder. That post can be found here.
Sunday, November 23, 2008
One data point that would be useful in getting a fuller picture would be the rate that new samples are being added to the que. If anyone has any information on that, please post it in the comments.
The article also gives a brief history of biometrics, starting with appearance (visual) and going through fingerprints (first recognized as unique 4 centuries ago!) and others until the recent methods of gait and DNA.
Saturday, November 15, 2008
Sunday, November 09, 2008
Monday, November 03, 2008
Saturday, November 01, 2008
K-Lite codec package update
X-rays made from Scotch(R) tape (hat tip to A.A.)
Superconductivity Can Induce Magnetism
Deaf people feel their way to speech
Seeing Through The Skin: Optic-less Imaging Technology Could Beat Lens-based Imaging Devices
HOWTO read the secret forensic dots in your laser-printer output
Biometric identifcation by body language
Audio bone headphones
Scientists Watch As Listener's Brain Predicts Speaker's Words
Hidden airport scanner will pinpoint terrorists
Police probe cell phones to catch criminals
How magicians control your mind
How forensic lab techniques work
Computers reassemble pieces of fractured archaeology
Review of Microsoft's Photosynth
Images of atmospheric optics
12 worst Photoshop mistakes ever
Darpa super-resolution vision technology R&D
How other senses adjust to blindness
Family name geographical profiler
Tuesday, October 28, 2008
The benefit from computer-assistance in analyzing video comes from the following:
- Volume (i.e. the sheer number of cameras and, hence, images to be monitored and/or analyzed)
- Concentration (i.e. the human visual system loses the ability to concentrate effectively on images after about 20 minutes of continuous viewing)
- Memory (i.e. computers can track and, possibly, predict more things simultaneously than a human can because, generally speaking, computers are not nearly as attention and working-memory limited in the short-term as humans and far outstrip us in their ability to recall video sequences over the long term - they can just play back the video recording off of their hard disks)
The article claims that the abilities of computer systems to recognize patterns is rapidly improving and approaching that of humans - that is no small feat as humans are simply amazing in their ability to perform real-time pattern analysis.
One intriguing point made in the article is that the current conflicts are generating a lot of real-world recordings of "bad behavior" that can be used to train and test new pattern analysis and prediction algorithms - training data like this is like gold to us signal processing types!
Thursday, October 09, 2008
EDN (USA technical magazine) has an article which contains more technical detail and pictures on the advance.
I should point out that this version of the artificial cochlea is not an exact replica in form factor (i.e. shape) or function of a natural cochlea. For instance, the artificial cochlea is planar in shape versus sea-shell-shaped; covers the frequency range of 4200 to 35,000 Hz versus the 20 to 20,000 Hz of the human ear; and isn't continually fine tuned by an external processor to focus on frequency bands of interest, like the human cochlea does when one is, for instance, one's brain is picking out a familiar voice in a cocktail party situation. I mention this not to detract from their excellent work, but instead to give you, curious reader, reasonable expectations as to its specifications and performance.
Friday, September 26, 2008
Thursday, September 25, 2008
Wednesday, September 24, 2008
"Ost said that people who were more likely to come up with false memories scored higher on a scale of "fantasy proneness" than those that did not." (My comment - "fantasy proneness" appears to mean "creative" in this context.)Although the article doesn't address it directly, previous studies have shown that accuracy of recall also depends greatly on the amount of time that has past since the event, which gives all the more reason to get witness statements soonest.
"Ost said that when DNA testing became available in the U.S. in the early 90s, 80 per cent of death row cases that were exonerated, were found to have been wrongly convicted on the strength of mistaken identity."
- GPU-based drawing of documents onscreen (for speed improvements)
- 64-bit for Windows (but not for Mac OS-X, at least yet)
- Expanded 3-D paint, lighting and rendering tools
Tuesday, September 16, 2008
In addition, here is a link to a BBC (British Broadcasting Corporation, UK) news story about the case and the analysis of the text message evidence. Very interesting stuff!
Sunday, September 14, 2008
Author's comment: It's a good thing that animals don't have privacy rights in the USA (yet!), or these scientists would be in jail for unlawful surveillance activities!
(Via Cross-Spectrum Acoustics)
Monday, September 08, 2008
Wednesday, August 27, 2008
PS. Thanks to C.S. for the link!
Using a testing technique adapted from studies involving infant hearing, researchers at the University of Rochester's Eastman School of Music and Department of Brain and Cognitive Sciences were able to test for perfect pitch in a random sample of people, including people with no musical training whatsoever. In the past, these tests were performed only on people with musical training who could identify notes by name. For more on this study, follow this link.
Wednesday, August 13, 2008
Saturday, August 09, 2008
Friday, August 08, 2008
Thursday, July 24, 2008
Monday, July 14, 2008
Saturday, July 12, 2008
Friday, July 11, 2008
The ScienceDaily article says that 17 percent of Americans suffer from tinnitus, but I am not sure what that statistic means - is it "suffer from at some point in their lives", "continually suffer from" or what? It seems from anecodatal evidence to be "continually suffer", but that is besides the point. It will be a step forward if they have developed a safe and effective treatment.
Follow-up: I was speaking to an ENT (Ear, Nose, and Throat) specialist the other day and asked about this statistic of 17% of Americans suffering from tinnitus. He said that that statistic was compiled from medical records - in other words, the number of patients that reported tinnitus symptoms to their doctors. I unfortunately did not think to ask him at the time whether the raw data was then adjusted to account for other factors or not. He also said that taking certain prescription medications, such as Cipro, can result in long-term or permanent tinnitus and that the chances increase if the patient has existing hearing loss (presumably age- or exposure-related).
Wednesday, July 09, 2008
- the subject had not been exposed to the newly acquired accent before
- the new accent was still in her native language (english)
- even after two years of therapy, the new accent persists
But what does this have to do with forensics, you might ask? Well, for starters consider voice comparison and subject profiling both rely directly and indirectly on understanding how the speech-motor area functions and how accents develop. Fascinating stuff!
What I took away from these articles is that there are potential (probable?) health risks when used a high power levels, such as in crowd control applications, so researchers are looking at where it might be useful in low power applications - advertising is mentioned, of course.
As an aside, I noticed the continuation of a pattern that seems to appear with all less-than-lethal "weapons" (i.e. those technologies that seek to incapacitate, drive-off, etc, rather than kill the subjects) - namely, once you label a technology or technique as "less than lethal", this seems to consistently bring with it the hard requirement that it be 100% less-than-lethal in all conditions. Taken to its obvious conclusion, this pattern will make most, if not all, less-than-lethal development projects go bust at some point, for better or worse.
Monday, June 30, 2008
Tuesday, June 24, 2008
A very simple implementation of this technique is to take a picture on Day 1, then another picture from the same location and in the same direction on Day 2. Next subtract the two images from each other and see what is left over. All the things that did not change between the two images will disappear and only those things that changed will be left! In this case, what will be see on the "difference image" might be some disturbed gravel, tire tracks off the side of the road (assuming it is a road-side bomb emplacement) or, if the military guys are really lucky, what will be left is a bunch of guys standing around with shovels and a bomb as they work to put it in place. Neat (and helpful)!
Monday, June 23, 2008
With that small confession and short history out of the way, I got the urge today to share one of my favorite podcast courses with you - Physics for Future Presidents, by Richard Muller. His explanation of the issues and science around global warming alone is worth the cost of an MP3 player. You don't have to use iTunes to download it, but it is convenient if you do. Enjoy!
Tuesday, June 03, 2008
PS. On re-reading my post, I noticed that I did not supply any answer to the obvious question of "so what?". The reason this technique is particularly interesting is that it potentially provides additional forensic evidence that could identify participants in gun crimes. Imagine being able to re-open a "cold case", for instance a drive-by shooting, using nothing more than a spent shell casing (and a fingerprint database, of course). Hopefully, there will not be any hidden "gotchas" in the details and this technique will be able to fulfill its initial promise.
Friday, May 30, 2008
Thursday, May 15, 2008
Sunday, May 11, 2008
An interesting point in the article is that, at least in one real-world deployment of a commercial system, the biggest benefit was gained from simply telling the claimants that such a system would be used on them - which caused many to drop their claims prior to being "analyzed" by the system.
Thursday, May 08, 2008
The Audacity Team is pleased to announce the release of Audacity 1.3.5 (beta) for Windows, Mac and Linux/Unix. Changes include improvements and new features for recording, import/export and the user interface. Because it is a work in progress and does not yet come with complete documentation or translations into foreign languages, it is recommended for more advanced users. For all users, Audacity 1.2.6 is a stable release, complete and fully documented. You can have Audacity 1.2.6 and 1.3.5 installed on the same machine.Enjoy!
Saturday, May 03, 2008
Monday, April 28, 2008
These drafts, along with previously released good practices documents from SWGIT and other organizations, can be found on the IAI (International Association of Identification) website at this link.
(Hat Tip: MB)
Sunday, April 27, 2008
The latest development is that the security implementation of the technology has undergone another evolutional generation and is being introduced into the US market. The company's Powerpoint presentation provides additional insight, even though one point it makes is entirely inaccurate - the latest version of the Mosquito system measures the ambient sound level and adjusts the level that it plays the annoying tone to be 5 dB (decibels) above the ambient, which, contrary to what the presentation claims, is not the same as being the level of a whisper. I think I understand what they were trying to get across with this point, but the way it is stated is inaccurate and misleading.
This is a controversial, yet ingenious use of technology and biology. We are sure to hear more about this in the weeks and months to come.
(Hat tip: boingboing)
Wednesday, April 16, 2008
(Hat tip to Government Computer News)
Monday, March 24, 2008
First off, the Department of Justice (USA) is funding Professor Rich Sanders, of the University of Colorado, Denver, to establish a new National Center for Audio/Video Forensics. The full university press release can be found here. It is scheduled to be up and running in the fall of 2009.
Second, the South Carolina Governor's School for Science and Mathematics (USA) runs its popular Summer Science Programs (SSP) every summer. SSP is a residential summer camp for rising 8th, 9th and 10th graders from across the state. The reason I mention it here is that I have been asked to teach two one-week runnings of a new course entitled A Mathematical Tour of Forensic Science. If you are interested, you can find out more on their website.
Update: I am informed by the director of the SSP that students from outside of South Carolina are also very welcome to participate.
Monday, March 17, 2008
It isn't much of a stretch to see how these same concepts could be built into other video applications, such as CCTV systems, for instance. Don't be surprised if they don't work this into a future episode of CSI or similar television show (or the next James Bond movie, for that matter).
Tuesday, March 04, 2008
Upon reflection, it was a predictable next step. First we had the major advance of refocusing out-of-focus images by, in essence, building a correction lens, all in software. This is what allowed NASA (the USA space agency) to correct some of the Hubble Space Telescope images after it was put into orbit with an out-of-focus optical chain.
But it one can simulate a lens well enough to correct an image, even if imperfectly, why not replace the real lens with a simulated one and focus the unfocused image received by the (lens-less) sensor? That is what the team at Argonne National Laboratory (Illinois, USA) is working on. Of course, simulations are rarely, if ever, as good as the real thing in all aspects, but if for their particular problem (X-ray imaging) the simulated lens is better than their real one, then they will have improved the imaging system and advanced the state of the art yet again.
Friday, February 29, 2008
Monday, February 25, 2008
As you can probably figure out from the intro, I have to give you my sincerest apologies, but work is leaving no time for thoughtful comments or analysis, so here are the links to the raw material that I hoped to turn into interesting posts:
Talk to the machine (Strategy Page)
Listening in with the council's lie detectors (Times Online; hat tip to A.F.)
Music Special: Five great auditory illusions (New Scientist)
Astronomy Technology Brings Nanoparticle Probes Into Sharper Focus (Science Daily)
Wanted: RAM's help in solving crimes (New Scientist) (a YouTube video explaining the attack can be found here)
Snakes Locate Prey Through Vibration Waves (Science Daily)
The 'non-lethal' flashlight (New Scientist Blogs)
Car Camera Recorder Pro: Video of Everything in Your Car's Path (TechnoRide)
Abuse of Auto-Tune (Cross Spectrum)
Justice Grants will Fund Research at CU-Denver (Business Journal)
FBI wants palm prints, eye scans, tattoos (CNN)
Enjoy! I hope to be back with more in-depth blogging soon.
Monday, February 18, 2008
I recommend reading the entire article. Enjoy.
So how loud is too loud?
The ideal sound level for normal conversation is 55 to 65 decibels. When the ambient noise rises to about 70 decibels, you have to raise your voice to be heard. At 75 decibels, conversation is difficult. Above 85 decibels, prolonged exposure - more than eight hours - can permanently damage your hearing.
While restaurant noise levels aren't a threat to hearing loss, "they are certainly an issue for communication. Many, if not most, restaurants have noise levels that are too high for comfortable conversation," says Christine Harrison, an occupational audiologist with the Workers Compensation Board of British Columbia.
The only problem is that this technique is not new to mankind. It has been used by humans since at least the 1800s, as evidenced by historical accounts of James Holman, nicknamed the "Blind Traveler" for his use of echolocation to travel the world.
Just in case I've lost you by immediately launching into correcting a historic inaccuracy, I will explain what human echolocation is. Simply put, it is the technique of using sound bouncing off of an object (i.e. echoes) to sense where the object is. Blind people have been taught this technique for years, hence the metal tip on the end of the traditional "white cane" used by many blind people over the years to tap the ground as they walked. The technique seems to have decreased in popularity since the widespread introduction of seeing-eye dogs (Note: this is an educated guess based on my own understanding of history, so if I'm wrong, please feel free to correct me!).
Despite the errors in the article and YouTube video, I am excited that this technique is being reintroduced for the benefit of those with impaired vision.
Sunday, February 17, 2008
- The frequency of the noise matters. High frequency noises can be reduced or eliminated by light-weight materials such as fiberglass, curtains, carpet, and rubber seals (e.g. around doors). Reducing low frequency noise requires MASS; in other words, it takes heavy materials to absorb the large amounts of sound energy contained in low frequency noise, such as from machinery, engines, air handlers, and the like.
- Solid-core doors can make a big difference in the amount of sound coming from the hallway (or leaking out into it, for that matter) and cause little, if any, disruption to the work environment when used to replace existing hollow-core doors. Most doors that come standard in home and office environments are hollow in the middle and therefore don't absorb low frequency sounds very well at all.
- If the room has a drop (also called a "false") ceiling, then replacing the standard ceiling tiles with acoustic ones can make a significant difference and is minimally disruptive.
- Wall and door treatments, such as barium-loaded vinyl hangings and acoustic panels, offer the benefit of being able to be installed to an existing room without requiring tearing down the walls, but installing them may require significant effort and it will almost certainly be quite disruptive to the existing workspace (think about shelves and such that are on the walls).
- If you have hollow walls (e.g. gypsum board on stud), then blowing insulation into the wall cavity can reduce middle and high frequency noises without being too disruptive.
- If full-scale remodeling is an option, consider adding an extra layer of gypsum board or other massive material to the walls. If you go this route, then you should advise the workers to install the boards so that the seams (between boards) of the new layer do not over-lap the seams of the underlying layer. Of course, there may be complications with window and door frames fitting the non-standard thickness of the walls, but a competent carpenter can solve those issues.
- Speaking of windows, if the building is located in an area where the external noise (e.g. vehicular traffic or aircraft) is an issue, then it will likely make things much simpler if you pick a room without a window for your lab in order to avoid having to acoustically shield it. Likewise, locating away from internal noise sources, such as elevators and air-handlers, is also a good idea where possible.
- Quieting noises in your lab itself is also a good idea. Computer workstations and other electronic equipment fans are the usual culprits here. A variety of options now exist for quieting computers ranging from low-noise replacement fans to liquid cooling systems that can be added to existing computers.
- If the acoustic environment is so poor that you need to go beyond the simpler of the measures listed above, then consider getting professional help (i.e. a consultant who specializes in this area) to evaluate the situation and recommend appropriate steps.
- Choosing a room that isn't a strict rectangular box can be a good idea as it can mean significantly less resonance.
Sunday, February 03, 2008
As far as industry addressing possible technology drawbacks of the equipment, the Guardian (UK, left-wing newspaper) reports that Hitachi has started fielding a new type of biometric technology - finger vein scanners. Finger vein scanners differ from finger print scanners in that they are reportedly more difficult to fool. The principle of operation in similar to the blood oxygenation sensors commonly used in medical settings - i.e. shining a light onto (into) the skin of the finger which is absorbed by the hemoglobin in the capillaries, thereby allowing the imaging sensor to "take a picture" of the capillary pattern. These patterns are reportedly unique to an individual, just like finger prints. Of course, it all depends in how you implement the matching algorithm, but that is another issue - for more, see the Journal of Forensic Identification paper on errors in fingerprint examination.
Whether the scanners address the cost issue I mentioned above remains to be seen. For more details, including one disturbinging case of how a gang got around a finger print scanner to steal an automobile, you can check out the Guardian article.
Thursday, January 31, 2008
EETimes has the story.
Monday, January 21, 2008
Sunday, January 20, 2008
G-Spot is a software application developed by Steve Greengerg to identify what codec is needed to play a video file. Given the plethora of low-cost digital video recorder (DVR) security systems on the market, many, if not most, with their own proprietary codecs, G-Spot can be a life saver. Here is a link to a review of the application (Note: there is some sexual innuendo, but I did not find it to be overly crude).
Now you know what drives many video examiners to distraction every day and what they turn to for the answer.
The researchers used functional magnetic resonance imaging to map the brains of musical conductors and non-musicians who tried to distinguish musical tones while also being shown visual images. The scans showed that non-musicians had to turn off more of their visual sense than the conductors did in order to focus on the task. One of the researchers, Dr. Hodges, director of the Music Research Institute at UNC-Greensboro, says there are two possible interpretations of the results:
One is that the brains of musicians are wired this way, and that’s why they became musicians. The other is that they train their brains for rewiring. Because conductors have to be able to hear a bad note, then identify who did it, perhaps they rewire their brains to combine their visual and auditory senses. An experienced conductor has trained day after day, year after year, to let their brains pick up various signals from their senses.
The article is quite good and highly worth reading through.
Thursday, January 10, 2008
Stereo from a single box (Blumlein was an audio genius. If you are an audiophile, I suggest you read a biography on him sometime.)
How the iPhone blew up the wireless industry
Acoustic superlens could mean finer ultrasound scans
Ultra-thin digital voice recorder
Noise reduction technology for cell/mobile phones (Note that the sales spiel uses words like "crystal" and "pristine" but you can clearly hear artifacting at low levels. Not trying to be overly critical, but couldn't they have let the results speak for themselves without the spin?)