I think the idea with adaptive noise cancellation is this: you have a dual microphone system. One channel is the primary channel (collecting the target sounds). The second channel is the "noise collection" channel. Through some mathematical algorithms, you subtract the noise collected in the "noise" channel from the primary channel (e.g., a different microphone aimed at collecting the cricket sounds or the katydid sounds, perhaps using a slightly lower gain setting, so as /not /to pick up distant flight calls being collected in the primary channel). The resulting signal in the primary channel should have reduced cricket and katydid sounds. Well, that's the theory, I guess.
Here's an older paper abstract from 1975. Current technology can probably do this adaptive noise filtering in very real-time. http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1451965 Sincerely, Chris T-H Michael Lanzone wrote: > It's worth playing with... I would be worried about loosing thrushes > and other spp in 3-5kHz range in the mix though, but if it worked well > would solve a huge problem. > > Mike > > Sent from my iPhone > > On Aug 21, 2009, at 10:09 PM, Chris Tessaglia-Hymes <[email protected]> > wrote: > >> Aha! I did a little searching. It looks like it is possible to cancel >> out the unwanted sounds, real-time. My first result was this, which >> describes adaptive noise cancellation technology: >> >> http://www.developer.com/java/other/article.php/3599661 >> >> Sincerely, >> Chris T-H >> >> Chris Tessaglia-Hymes wrote: >>> So, the question is: can the unwanted cricket and katydid sounds be >>> removed from the audio channel at the time of sound acquisition, >>> real-time, such that their acoustic signatures are minimized or >>> eliminated altogether from the collected sound data prior to an >>> automatic detector batch process? >>> >>> Sincerely, >>> Chris T-H >>> >>> Michael Lanzone wrote: >>>> No software we have worked with gets near 100%. I have toyed around >>>> with templates that got 95% of the calls, and detectors can get >>>> ~90%, but more commonly get in the 60-80% range. In Louisiana with >>>> the insects it would be on the low end of this. Katydids and such >>>> are problematic for detectors... >>>> >>>> Best, >>>> Mike >>>> >>>> Sent from my iPhone >>>> >>>> On Aug 21, 2009, at 7:43 PM, Erik Johnson <[email protected]> >>>> wrote: >>>> >>>>> Hi All, >>>>> >>>>> I've been recording from my home in south Louisiana with set-ups like >>>>> Chris and David over the last few years. I've been using the oldbird >>>>> software (tseep, etc), but only get about 20% of the flight calls >>>>> that >>>>> I would otherwise detect by ear (and visually on spectrographs). Not >>>>> only is the detection software missing many calls, it's also >>>>> underestimating the richness that I could get. In one of my best >>>>> fall >>>>> nights I more than doubled the species richness by listening through >>>>> the entire night compared to running it through the software. What's >>>>> also frustrating is that I get a TON of trash clips - many more than >>>>> birds clips. I've tried to filter out background noise (which is >>>>> mostly insects and air conditioning units) before running the file >>>>> through the auto-detect software, but it doesn't change the results >>>>> much. I haven't toyed with the other programs that have been >>>>> mentioned in this threat, but as I understand it, they also don't get >>>>> near 100% - or am I wrong - it sounds like this technology improving >>>>> quickly. This list serve is giving me new inspiration to hook up the >>>>> mic this fall and to play around with more settings and programs. >>>>> I'm >>>>> eager to see the upcoming manuscript and to hear everyone's thoughts >>>>> on this subject! >>>>> >>>>> Happy listening, >>>>> Erik Johnson >>>>> Lafayette, LA >>>>> [email protected] >>>>> >>>>> -- >>>>> NFC-L List Info: >>>>> http://www.NortheastBirding.com/NFC_WELCOME >>>>> http://www.NortheastBirding.com/NFC_RULES >>>>> >>>>> http://www.mail-archive.com/[email protected]/maillist.html >>>>> -- >>>> >>>> -- >>>> NFC-L List Info: >>>> http://www.NortheastBirding.com/NFC_WELCOME >>>> http://www.NortheastBirding.com/NFC_RULES >>>> >>>> http://www.mail-archive.com/[email protected]/maillist.html >>>> -- >>>> >>> >> >> -- >> ============================================= >> Christopher T. Tessaglia-Hymes >> TARU Product Line Manager and Field Applications Engineer >> Bioacoustics Research Program, Cornell Lab of Ornithology >> 159 Sapsucker Woods Road, Ithaca, New York 14850 >> Voice: 607-254-2418, FAX: 607-254-2460 >> http://www.birds.cornell.edu/brp mailto:[email protected] >> ============================================= >> >> >> -- >> NFC-L List Info: >> http://www.NortheastBirding.com/NFC_WELCOME >> http://www.NortheastBirding.com/NFC_RULES >> >> http://www.mail-archive.com/[email protected]/maillist.html >> -- > > -- > NFC-L List Info: > http://www.NortheastBirding.com/NFC_WELCOME > http://www.NortheastBirding.com/NFC_RULES > > http://www.mail-archive.com/[email protected]/maillist.html > -- > -- ============================================= Christopher T. Tessaglia-Hymes TARU Product Line Manager and Field Applications Engineer Bioacoustics Research Program, Cornell Lab of Ornithology 159 Sapsucker Woods Road, Ithaca, New York 14850 Voice: 607-254-2418, FAX: 607-254-2460 http://www.birds.cornell.edu/brp mailto:[email protected] ============================================= -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/[email protected]/maillist.html --
