Thursday, December 30, 2010

Forensic Audio: An Introduction

A colleague and former student of mine, Detective Phil Manchester (UK), wrote an excellent article earlier this year titled "An Introduction to Forensic Audio".  It appeared in the British audiophile magazine Sound on Sound.  I highly recommend reading this short overview of audio forensics.


Wednesday, December 29, 2010

Crime Scene Investigation: Photographic Portfolio

A former forensic crime lab technician turned professional photographer named Angela Strassheim has used her fascination with crime scenes to create a photographic portfolio.  For the portfolio, she visited dozens of former crime scenes and photographed them using a combination of low light, long exposure times, black and white film, and a chemical reagent used to highlight blood stains.  The results are fascinating and you can see them here.

Monday, November 22, 2010

Music: The Humanthesizer

What can a group of engineers and a musician do with a computer, a sound card, a bunch of dancers, a singer, and a bucket of conductive paint? Create the Humanthesizer!

A bit of fun for a Monday morning - enjoy!

PS. I recommend watching "The making of..." clip first and then the actual performance.
PPS. A "boffin" is a scientist/engineer in British slang.

(Hat tip - Thanks Robert C!)

Audio Forensics: Voice Risk Analysis Fails Practical Trial

Voice Risk Analysis (VRA) has always been viewed skeptically by many in the speech field. This technique takes Voice Stress Analysis - i.e. analyzing speech for microtremors and possibly other indicators of nervousness, anxiety, and general stress - and applies it to a real world problem. As far as the science of strict voice stress analysis goes, it is believable to me based on my own observations. I have seen that many people can exhibit audible stress in their voices when under emotional or physical stress.  As an experiment, try listening to someone on the phone when they are climbing a set of stairs rapidly and you should notice a difference!

Voice Risk Analysis takes this concept and extends it to the automated detection of deception (lying) over telephone calls.  Is this completely unbelievable on the face of it? Not completely - you may have occasionally encountered people who sound nervous when trying to lie.  However, pricey products have been sold based on extrapolating this a step further to claim that simply by analyzing telephone speech to a finer level of detail (e.g. looking for microtremors) one can detect stress and even lying in the general population.

The Guardian (a center-left news organization in the UK) has a news article on the results of practical trials conducted by the British government using a commercial VRA system to attempt to catch people lying in telephone interviews regarding government-funded benefits. After analyzing the results from 45,000 calls, the bottom line was that the system did not provide enough value to justify its cost.  Given the history of VRA and my own understanding of speech science, I am not surprised at all by the findings.  Hopefully, as a matter of public policy, this will put an end to government purchases of VRA technology until such a time as it is proven by peer-reviewed studies to work for the application(s) it is intended for.

Friday, November 19, 2010

Photography: Preserving old photos and documents

One of my favorite websites, lifehacker, has an article based around material by Lynda Schmitz Fuhrig, the electronic archivist for the Smithsonian Institution Archives, on how to best preserve old photographs and other documents. This topic is very important for forensic examiners and the legal system in general as, at least in the USA, we have to preserve evidence for at least 25 years in case there is ever a re-trial.

For information about the long term care and handling of DVDs and CDs, I highly recommend the National Institute of Science and Technologies guide to the subject, available in PDF format (size = 1.24MB) at the following link.


Monday, October 11, 2010

Forensic Education: Upcoming Audio Forensics Workshop

I would like to pass along the following announcement:

The National Center for Media Forensics at the University of Colorado Denver will be holding an Audio Forensics Workshop December 13-15, 2010 in Denver, CO.  This course is an introduction to digital audio, acoustics, audio evidence admissibility, and recorded speech enhancement.  It is the perfect experience for those new to the field, practitioners needing to review forensic audio theory and practice, or those accustomed to working with other types of digital and multimedia evidence.  Course topics include:
·       Introduction to Media Forensics
-        Overview and principles in Media Forensics
-        Admissibility of audio evidence
·       Foundations for Forensic Audio Enhancement
-        Sound and acoustics
-        Audio recording and playback
-        Digitization of sound
-        Signal processing and enhancement algorithms

·       Demonstration and Practice
-        Digital evidence seizure and acquisition
-        Enhancement practice
-        Notes and report writing
-        Preparation of enhanced material
The course will be co-taught by Dr. Catalin Grigoras and Jeff M. Smith.  The cost for this class is $850 and graduate level university credit will be given upon completion.  

Tuesday, September 14, 2010

Human Visual System: Gene identified that causes short sightedness

The BBC (center-left news, United Kingdom) reports on research at King's College London that has tentatively identified a gene that causes myopia, commonly known as short-sightedness.  For those who confuse short and long sightedness, just remember that they are what their names say - you see objects better at short distances when short-sighted and you see objects better at long distances when long-sighted.  The article is well written and has graphics to explain the condition.

Human Speech System: Woman's migraine causes French accent

A woman in the United Kingdom is suffering from Foreign Accent Syndrome - a rare condition caused by damage to the brain that results in changes to a person's accent. In this case, the woman went from a British accent to a French one.  The Guardian (UK, left-wing newspaper) has the story.  Fascinating.

Image Forensics: Bad "Photoshopped" Mad Men cover on Rolling Stones

The title of this post says it all - the writers at Jezebel (a celebrity news for women) wrote about it first. See for yourself.

Monday, August 30, 2010

Linguistics: Challenge Puzzles

Here is a fun website with lots of puzzles - from easy to hard - involving linguistics.  Enjoy!

(Hat Tip:, USA, technology news)

Thursday, August 26, 2010

Human Speech System: Test your lip-reading ability

Speech scientists have long known that seeing individuals can, even unconsciously, use lip-reading to assist in decoding words spoken in a conversation. (Note: lip-reading words spoken randomly, without context, is very difficult).  This entertaining and challenging puzzle (link to a Wired on-line article entitled A Classic Back-to-School Lip-Reading Puzzle) will test whether you can match a given list of names to faces in an illustration by lip-reading, given the context that each boy in the illustration is on the verge of pronouncing his name.


Friday, July 30, 2010

Admin: Apologies and "make up" for light posting

Hi, All.
It has been a very hectic summer for me (again), but I'm back to blogging (finally).

I offer the following website and comic as a sort of "make up" for my delinquency.


(Hat tip to EE Life)

Monday, May 17, 2010

Science Education: The Listen Project

My local newspaper (Charleston's Post and Courier) had a blurb in the comics section this week that mentioned a good resource for kids (at heart) to learn about audio. It is the Listen Project and can be found on the Exploratorium's website.  It seems to live up to its tag line of "Explore the art and science of listening".  I highly recommend it.

To give credit where credit is due - the project is funded by the National Science Foundation, the Gordon and Betty Moore Foundation, The Bernard Osher Foundation, and the National Endowment for the Arts.


Monday, April 05, 2010

Science Education: Summer Science Programs in Forensics

The South Carolina Governor's School for Science and Mathematics (USA) runs its Summer Science Programs (SSP) every summer. SSP is a residential summer camp for rising 8th, 9th and 10th graders. Both in-state and out-of-state students are accepted.

I'll be teaching two, one-week runnings of my course, A Mathematical Tour of Forensic Science, again this year.  In addition, Dr. Sid Parrish will be teaching his ever popular CSI (Crime Scene Investigation) course.  For those who, for some unimaginable reason, might want to take courses in subjects unrelated to forensics, there are a large number of offerings (Lego Robotics, Great Experiments in Physics, and more).  If you are interested, you can find out more on their website. I hope to see you there!

Saturday, March 06, 2010

Science Education: Popular Science Magazine puts entire archive online for free viewing

As a kid growing up in the USA in the 70's, I spent a lot of time in my local public library reading everything I could get my hands on.  When it came to science and technology magazines, I remember reading every single Popular Mechanics, Popular Science, and Scientific American as soon as it came in. Of course, a lot of what was in Scientific American was written above my academic level, but with each issue I read I got a little further into each article before I was lost- over time I gave myself a pretty good science education that way. (Aside: of course, that was before Scientific American became so politicized, but I can expound upon the politicization of science and science journalism another day...).

This trip down Memory Lane has a pleasant destination - Popular Science Magazine has put its entire archive of back issues - complete with period advertisements- online for free viewing.  The archive is even searchable using Google's technology.  Very cool, in a geeky sort of way (yes, I was a geek before geeks became cool).


Thursday, March 04, 2010

Speech Recognition: Men harder to understand than women

Researchers at Stanford University (USA) and the University of Edinburgh (UK) have tested various automatic speech recognition (ASR) systems and found that in general they have a more difficult time recognizing speech from males than females.  One of the causes mentioned by the researchers was that the men tended to use fillers such as "emm" more often.

I should point out that the tests were conducted using recordings of telephone calls.  This is important because the type of "channel" the audio is being carried over makes a significant difference to a computer-based speech recognition system.

The work was sponsored by the US Office of Naval Research.

For a quick overview of the research, you can read the BBC (center-left news media, UK) article here.


Tuesday, February 23, 2010

Human Auditory System: Audiences hate modern classical music because their brains can not cope

I guess there is a scientific reason "modern" classical music sounds so awful to my ear after all!  The Daily Telegraph (center-right newspaper, UK) has the story.

Saturday, February 06, 2010

Human Visual System: Caucasians and Asians recognize faces and expressions differently

World Science (an online science news site) summarizes work by researchers at the University of Montreal (Canada) into how Asians and Caucasians differ in recognizing faces and facial expressions.  Eye tracking cameras were used to monitor where the subjects were gazing.  Doctoral candidate and researcher Caroline Blais said that
The study confirmed that Caucasians study the triangle of the eyes and mouth, while Asians focus on the nose..
 In a separate study, she also tested how recognition of facial expressions differed between the two ethnic groups. It turned out that Asians were not as accurate at recognizing emotions that required observing the mouth, such as fear, disgust, and anger.

The two studies were published in the journals Current Biology and PLoS One.

Monday, February 01, 2010

Acoustics: Visualizing whale calls as art

NewScientist (science magazine, UK) has a fascinating set of images from Mark Fischer, who uses artistically manipulated wavelet transforms of the calls of marine mammals to create stunning artwork.

Monday, January 18, 2010

Science and Math: Another round-up of interesting links

I have been having difficulty finding enough time to write my normal analysis and commentary on the information I have come across. Therefore, in order to not fall any further behind in getting interesting things out to you, I'm going to once again resort to listing the links.

With apologies, here they are:

US Judge rules that computerized voice stress analysis can be used to monitor offenders  (note: I've blogged previously about how detecting stress is NOT the same as detecting a lie)

Mathematicians: An Outer View of an Inner World

NASA Interstellar Boundary Explorer Mission

Forensic Audio overview article

Mysterious spiral lights
(solution: failed Russian missile launch)

Victorian Infographics

Virtual tours you don't want to miss

Saturn at equinox

The secret life of chaos