trixter aka Bret McDanel wrote: > I will give you one of my super secret someday projects. A voice stress > analyzer built into asterisk (would be done in a similar way in terms of > interfacing, perhaps just play a beep or if non voice only circuit send > text).
:) Nice! > VSAs work by detecting subharmonics present when a person is under > stress. Basically when stressed there are slight increases in muscle > tension that pull on vocal cords this causes a specific set of > sunharmonics to shift upwards slightly. Applying a dsp filter to that > and detecting those changes will result in a stress indicator. The key is changes. Changes to base - i.e. can't start call by lying :) > Most people are conditioned to believe lying is wrong (whether or not it > is I wont comment here). As a result they exhibit stress when they lie. > This is how a polygraph works, by measuring physical responses to what a > subject thinks is wrong. Kewl. > While this is not that accurate, you dont know what is causing the > stress, you can see when it presents itself in relation to what is > spoken and try to make some guesses. Yep. > The frequencies are generally between 8-14Hz. While these frequencies > by themselves generally cannot pass a telephone network (300-3300Hz US > 300-3400Hz EU typically) when mixed with other frequencies they can be > passed. This is the same principle that china used for its C5 links > with america, a 2600+2400+60Hz tone followed by 2400Hz would seize the > line there (at least a few years ago, I dunno about now, or even if they > are still C5r1). 60Hz by itself cant go but it modifies the waveform of > the other tones and can be pulled out. Wouldn't you also need a base recording of someone not lying? Otherwise wouldn't you end up saying people with deep voices lie? > Now you have an all new super secret someday project so your list doesnt > get shorter ! :) HEHE!!! You da man! -- Cheers, Matt Riddell _______________________________________________ http://www.sineapps.com/news.php (Daily Asterisk News - html) http://freevoip.gedameurope.com (Free Asterisk Voip Community) http://www.sineapps.com/rssfeed.php (Daily Asterisk News - rss) _______________________________________________ --Bandwidth and Colocation sponsored by Easynews.com -- Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users