Imaging: Improvements in through-wall radar imaging

StrategyPage has a short article about the two latest versions of through-wall radar imagers (namely the Xaver 400 and RadarVision). These devices allow soldiers and police to see objects, including people, on the other side of a wall made of standard building materials, such as concrete, wood, gypsum board (a.k.a. drywall), and the like, but not metal.

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.

Enjoy!

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.

Biometrics: Request for automation to reduce FBI backlog

The StrategyPage has a short article on the backlog facing the FBI in analyzing DNA samples - 40,000 samples in the que with a work-off rate of 4 samples per week! Automation will reportedly improve the work-off rate to 200 samples per week.

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.

Enjoy!

Fun: Sew me the music

Gizmodo highlights a sewing machine by SOUNDS.BUTTER that stitches the time-amplitude waveform of the sound.

Image Forensics: Was North Korean leader's photograph tampered with?

A photograph was released by the North Korean government last week that purported to show Kim Jong-il, their national leader, reviewing military troops - and looking suspiciously healthy after reportedly suffering a stroke. The Times Online and BBC (both center-left UK newspapers) report on the discrepancies in the photograph, including mismatching shadows and a missing black line.

Fun: All of Murphy's Laws in one place

Murphy's Laws, the Complete Collection (or so they claim!).

Enjoy!

Physics: A round-up of recent interesting links!

My aplogies for my light posting of late. Outside commitments have kept me from posting nearly as much as I would like. Here is a collection of links that I have saved up over the last several weeks to blog about. I hope you enjoy them, but please note that some of these are not serious, scientific articles - just because it can be found on the Internet doesn't make it science, much less forensic science! If you are particularly interested in any of the topics addressed below, just let me know and I'll delve further in a future posting.

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

Sound-card oscilloscope

Audio bone headphones

Scientists Watch As Listener's Brain Predicts Speaker's Words

Hidden airport scanner will pinpoint terrorists

Overpaid professions

Military camouflage

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

Image Recognition: Military requirements push technology forward

The Strategy Page has an article about how the proliferation of video on the battlefield (e.g. from surveillance cameras and even night vision goggles) is driving technology development. Initially, it was the UK (United Kingdom) that drove image recognition technology with its massive deployment of CCTV in public spaces (e.g. train stations, airports, city centers, and shopping malls). Now, it is the military.

The benefit from computer-assistance in analyzing video comes from the following:

1. Volume (i.e. the sheer number of cameras and, hence, images to be monitored and/or analyzed)
2. Concentration (i.e. the human visual system loses the ability to concentrate effectively on images after about 20 minutes of continuous viewing)
3. 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!

Enjoy!

Human Auditory System: Artificial Cochlea

A next generation implementation of an artificial cochlea has been developed by researchers at the University of Michigan and Tufts University (both in the USA). The natural cochlea is the sea-shell-shaped structure in the human auditory system that is the final stage in the conversion of air pressure variations (a.k.a. sound waves) into neural impulses that convey the frequency and amplitude information information contained in the sound to the brain for interpretation.

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.

Evidence: Study of the impact of CSI-style shows on jurors

An overview of the study by researchers at the University of Leicester can be found at Science Daily.

Audio Forensics: New LinkedIn Forensic Audio Group

Phil Manchester (Force Forensic Audio Specialist, West Midlands Police, UK) has just started a Forensic Audio Group on LinkedIn, the popular professional networking web-service. He plans to use it not only as a way to connect people working or interested in this field, but also as a forum for discussions related to it. I have just joined up myself and I encourage you to do the same if you are keen on audio forensics. The basic membership in LinkedIn is free of charge, as is membership in the group.

Testimony: Memory is fallible, study confirms

Cosmos (Australian, popular-science magazine) has an article on research by James Ost, University of Portsmouth (UK) into the accuracy of recall, in this case, of video news reports seen some three months prior. There were a couple of interesting statements that popped out at me:

"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.)

"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."

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.

Image Forensics: Adobe launches CS4

Adobe has launched the latest version of its Creative Suite, which includes, most importantly for image/video forensic types, Photoshop. Headline features of Photoshop CS4 include:

• 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

Hat tip: Ars Technica

Linguistics: Forensic Linguistics used on text message evidence

Dr Tim Grant, Deputy Director of the Centre for Forensic Linguistics at Aston University (UK), is well known in forensic linguistic circles. ScienceDaily has excerpts from an interview with Dr. Grant following the successful conviction of a murderer that relied partly on Dr. Grant's testimony about text messages allegedly sent by the suspect (since convicted) to throw investigators off the trail. I call your attention to the careful and correct use of the phrases "unlikely" and "more likely" to describe the results of the analysis, instead of a phrase such as "proved conclusively".

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!

Acoustics: Listenging to nature

Using microphones to capture the sounds made by animals in their habitat, minus humans and their man-made sounds. These sounds are known as the "biophony" and are used to sense the quality and character of the animals' habitat. Wired has the story.

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)

Fun: Top Ten Amazing Physics Videos

Wired has them. Enjoy!