Admin: Word verification requirement for comments

Due to an overly burdensome and increasing amount of spam comments, I have turned on word verification for all submitted comments. I hope that this has not inconvenienced anyone.

Kind Regards,

Keith

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!

Human Auditory System: Foreign subtitles improve speech perception

Want to improve your ability to comprehend a second spoken language? One way is to watch foreign films and read the foreign language subtitles - not the English ones. Eurekalert reports on a recent study.

Human Auditory System: Newborn babies cry with mother's accent

MedGadget reports on a study by French and German scientists on accent that a newborn uses - conclusion: its mother's. It is well known that a person's hearing system begins functioning while still forming in the womb. I find it fascinating that it is also "training" the speech part of the system at the same time and that the interplay works so soon after birth.

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!

Audio: Laser microphone patented

Wired.com reports on a new type of microphone designed and patented by David Schwartz. The principle behind the design involves a laser beam measuring the vibrations of smoke particles in a tube as they are deflected by sound. There are two interesting video clips on the Wired.com page - one showing a demonstration of the second prototype and the other showing the components of the device.

Enjoy!

Biometrics: FBI to migrate to multi-modal biometrics

COMPUTERWORLD reports on the FBI (Federal Bureau of Investigation, USA) announcement at the Biometric Consortium Conference that it will migrate from its IAFIS fingerprint database to a new multi-modal biometric database that will include DNA records, 3-D facial imaging, palm prints, and voice scans.

Image Forensics: Seeing is NOT believing

Spectrum Magazine (by the Institute of Electrical and Electronic Engineers, or IEEE, USA) has an excellent overview article on detecting tampering in digital photographs by Professor Hany Farid (Dartmouth College, USA).

Enjoy!

Human Auditory System: The Power of the Pentatonic Scale

Here is a link to a video of Bobby McFerrin (a famous jazz and a cappella musician) demonstrating the power of the pentatonic music scale at the World Science Festival 2009. Short and fascinating!

Enjoy!

Admin: Posting will be light

Due to a continuing heavy travel schedule, posting will be light for a while.

Education: Yenka Light and Sound modeling software

I've been using Falstad's freeware Java applets for teaching acoustics and oscillation concepts in the classroom for years now. I recently decided to give Crocodile Clips' Yenka Light and Sound modeling software a try after some of my own children enjoyed using it in school. At first it was to take advantage of the free license for home use (yes, FREE). Now, however, I'm going to use it in classes thanks to the numerous models already built-in and even more content online. My favorite built-in model so far is "Speed of Sound" - which lets you add other media, such as vacuum, water, and wood, and see how the speed of sound changes and then interacts with the sound wave in air, assuming it exits the extra media at all - very cool!

Not to leave optics out, there are informative models for angles of reflection, refraction, mirrors, lenses, telescopes, and more. For instance, to show that the angle of incidence equals the angle of reflection, the student drags two protractors into the workspace and measures both angles as the (virtual) beam of light bounces off the mirror. Simple, but effective. Many more sophisticated models are available too, plus you can build your own and save them for later use (as an educator, I like that).

Yenka also covers more than the physics of sound and light - mathematics, chemistry, computers, electronics, and other packages are also available. I've tried the chemistry package with my boys. Being boys, they were particularly pleased with being able to experiment with (virtual) dangerous substances after having to suffer through the kid-safe chemistry sets sold in stores these days.

Crocodile Clips is based in the UK, so American and other visitors to their website may not understand the references to terminology used in the British education system. Luckily, the laws of physics do not change as a result of the software leaving the UK! Yenka is a free download for students to use at home. Use outside of the home requires buying a license, of course. Finally, it works on Mac and Windows operating systems.

Enjoy!

Forensic Linguistics: Identify the language of a text

LangID is a new website that will identify the language of any text you can paste into its webpage or upload/tweet/email them with. This free service is based on the Google Ajax API (Application Programmer Interface) and currently identifies around 85 (human) languages with more being added. A list of the languages that it can identify can be found at this link.

(Hat tip: Good Morning Silicon Valley)