Science Education: Summer Science Programs in Forensics

It is that time of year again for students and parents - time for signing students up for summer camps!

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.

As usual, I'll be teaching two, one-week runnings of my course, Applied Forensic Science (formerly: 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 Classical Physics, and more).  If you are interested, you can find out more on their website. I hope to see you there!

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.

Enjoy!

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.

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.  

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.

Enjoy!

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!

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.

Enjoy!

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

Enjoy!

Audio Forensics: Signal Processing helps unravel JFK Shooting evidence

IEEE (The Institute of Electrical and Electronic Engineers) has started a public video section on its web site it calls ieee.tv.  I have been a member of IEEE since at least my graduate school days, as are many speech and forensic scientists, so if you are in either one or both of these fields and are not a member, I highly recommend that you check into it. (And in the spirit of full disclosure and in the hopes of avoiding investigation under who knows what new law is actually now or ever will be on the books about such things on the Internet - no, they didn't pay me to plug them as a professional organization!).

On to the subject of this post: ieee.tv has a fascinating video clip on the gunshot analysis performed by various experts on the recordings JFK assassination.

Hat Tip: Thanks Alex!

Audio Forensics: Pro Tools Snow Leopard Pre-Release

I don't use Pro Tools myself, but many audio forensics professionals do, so here is a breaking news item...

From Hitsquad Musician's News:

Pro Tools Prerelease now available for Mac OS X Snow Leopard

Avid/Digidesign is pleased to announce the immediate availability of a prerelease version of Pro Tools software that provides expanded Mac OS X 10.6.x Snow Leopard compatibility to Pro Tools 8 users.

Audio Forensics: Speech quality versus intelligibility

Engineering Technology Magazine (Institute of Engineering and Technology, UK) has a well written article concerning research by CLEAR (Center for Law Enforcement Audio Research) concerning the effect of noise reduction on intelligibility of evidentiary recordings and other audio in law enforcement situations.

... most speech-enhancement techniques improve sound quality at the expense of intelligibility, particularly when the signal-to-noise ratio (SNR) is very low. Closely related as they are, speech quality and intelligibility are not identical.

This is a classic trap that is easy for a novice to fall into.

Read it all.

(Hat tip: RH)

Human Hearing System: When an ear witness decides the case

The New York Times (USA) has an excellent article on human speech and hearing and how the vision system interacts with hearing.

Enjoy!

Filtering: Video clip explains Auto-Tune software

Nova's ScienceNOW by PBS (Public Broadcasting Service, USA) has an informative video clip on Andy Hildebrand's pitch-correction software called Auto-Tune. This audio filtering technology is used by professionals to correct mis-sung notes both in the studio and during live performances. It has been compared to Photoshop for voices.

Enjoy!

Admin: Summer Science Program in Forensics

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. I'll be teaching two, one-week runnings of my course, A Mathematical Tour of Forensic Science, again this year. If you are interested, you can find out more on their website. I hope to see you there.

Audio Forensics: Solving a Beatles' chord mystery

Dalhousie University (Nova Scotia) math professor Jason Brown has apparently solved a musical "who-dunnit" - what was the opening chord of the Beatles' famous Hard Days Night? There was an agreed upon suspect - namely George Harrison - but what was the chord? No one could reproduce it, even knowing what guitars they used in performances.

Enter Professor Brown. The professor used tools well known to forensic audio examiners - an FFT (Fast Fourier Transform) to analyze the spectrum and logic. And what did he deduce? It appears that George Harrision had a little help from someone else - perhaps the Beatles' manager, George Martin - who simultaneously played the chord on a piano! So, in the spirit of the board game Clue (Cluedo, for you Brits), it was George AND George, in the recording studio, with a guitar AND piano. Mystery solved!

Here is an article to read more about it. And another one. Enjoy!

(Hat tip to D.E. - thanks!)

Computer Audio: Latest Audacity beta (1.3.7) is released

Audacity 1.3.7(beta) is available for download. This release primarily seems to consist of bug fixes, but they do say that they added support for DirectSound, which is a widely-used Windows(R) DirectX API (Application Programmer Interface). Here is the text from their announcement:

Audacity (http://audacity.sourceforge.net/) is a fast multi-track audio editor and recorder for Windows, Mac, and Linux/Unix.


The Audacity Team is pleased to announce the release of Audacity 1.3.7 (beta) for Windows, Mac and Linux/Unix. This is primarily a bug-fix release to significantly improve stability and usability, especially on Mac OS X, but includes some new features too.

Cross-Platform Bug Fixes include:

* Muting/soloing caused incorrect channel results in exported stereo files
* Fixes for Nyquist effects, Compressor and Noise Removal
* Fixed Export as WAV could be corrupted if overwriting to same file, and Export Multiple to uncompressed formats only produced 16-bit WAV
* MP3 and WMA now export correctly with all supported metadata

Platform-specific Bug Fixes include:
* Windows Vista: crash opening Preferences
* Mac OS X and Linux: fixes for spurious clipping, label typing, no shortcuts after running effects, and project rate when importing files
* Mac OS X only: fixes for inactive or corrupted menus and hidden dialogues, portable settings, and Command and Control shortcuts. Also FFmpeg installer now available.

New features/other improvements:
* F11 Full Screen mode, high-quality "Sliding Time Scale/Pitch Shift" effect, Audio Contrast Analyzer
* Windows: sound devices can now be opened using the more efficient DirectSound API
* Improved latency correction using fixed correction value

See http://audacity.sourceforge.net/ for details.

Evidence: Listen to the raw audio evidence

If you would care to listen to the audio and read the transcripts of the Governor Blagojevich (IL, USA) wiretaps, here is the link.

Human Auditory System: Speech Intelligibility overview

A colleague pointed me to the following overview of speech intelligibility on the Sound & Video Contractor website. It was written for intelligibility during teleconferencing, but the information in it is directly applicable to audio forensics. Special attention should be paid to how reverberation and signal-to-noise ratio (SNR) affect intelligibility.

Enjoy!

Forensic Linguistics: Untangling Tricky Talk

I have a confession to make - I only got an iPod once a friend convinced me of the merits of university course podcasts. I've since become "addicted" to several technical, news, and business podcasts and would not have it any other way.

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.

Enjoy!

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.