Re: [nfc-l] Engineers - chime in? Adaptive Noise Cancellation

2009-08-24 Thread Michael Lanzone 
I will look to see if we do..

Sent from my iPhone

On Aug 24, 2009, at 9:54 AM, Thomas Fowler  wrote:

>
> Hi Everyone,
>
> I am an engineer chiming in.
>
> I have used this technique to clean up a signal.  Technically, it is  
> pretty simple to subtract out a "noise" signal.
> The hard part is getting a signal which is the exact "noise" you  
> want to subtract.  By exact I mean it has
> the equivalent gain, and timing and spectral content.  If it is in  
> the same frequency band as the target signal things
> get more difficult in a hurry.  Does anyone have multiple channel  
> recordings where the noise shows more prominently
> on one channel while the target bird shows better on another  
> channel?  I have Labview and can read *.wav files.  I would
> be willing to spend some time messing with this if someone can  
> provide a appropriate file.
>
> TomF
> retired Cornell Bioacoustics Engineer.
>
>
> At 01:00 AM 8/22/2009 -0400, you wrote:
>> Okay, last post for the night
>>
>> The more I read about this, the more and more it sounds really cool.
>>
>> So, you software and hardware engineer people out there - what do  
>> you think? Can it work to better clean up night flight call data  
>> collection? Heck, this could get you closer to that 90-95% positive  
>> detection figure we'd all like to see.
>>
>> http://plaza.ufl.edu/badavis/EEL6502_Project_1.html
>>
>> Sincerely,
>> Chris T-H
>>
>> Chris Tessaglia-Hymes wrote:
>>> 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
>

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Re: [nfc-l] Engineers - chime in? Adaptive Noise Cancellation

2009-08-24 Thread Thomas Fowler 

Hi Everyone,

I am an engineer chiming in.

I have used this technique to clean up a signal.  Technically, it is pretty 
simple to subtract out a "noise" signal.
The hard part is getting a signal which is the exact "noise" you want to 
subtract.  By exact I mean it has
the equivalent gain, and timing and spectral content.  If it is in the same 
frequency band as the target signal things
get more difficult in a hurry.  Does anyone have multiple channel 
recordings where the noise shows more prominently
on one channel while the target bird shows better on another channel?  I 
have Labview and can read *.wav files.  I would
be willing to spend some time messing with this if someone can provide a 
appropriate file.

TomF
retired Cornell Bioacoustics Engineer.


At 01:00 AM 8/22/2009 -0400, you wrote:
>Okay, last post for the night
>
>The more I read about this, the more and more it sounds really cool.
>
>So, you software and hardware engineer people out there - what do you 
>think? Can it work to better clean up night flight call data collection? 
>Heck, this could get you closer to that 90-95% positive detection figure 
>we'd all like to see.
>
>http://plaza.ufl.edu/badavis/EEL6502_Project_1.html
>
>Sincerely,
>Chris T-H
>
>Chris Tessaglia-Hymes wrote:
>>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


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Re: [nfc-l] Engineers - chime in? Adaptive Noise Cancellation

2009-08-21 Thread Ben Coulter 
I'm not a sound engineer, but it seems like if you pick up any portion of 
flight calls in the noise reference signal, you will end up removing or 
reducing the flight calls in the resultant recording, which would be extremely 
counterproductive.  So you would need to obtain a good recording of the ambient 
noise only that definitely doesn't include any energy from calls.  Perhaps 
there is a way to built a bucket baffle that would insulate the noise mic from 
the flight call sounds.

Cheers,
Ben Coulter

--- On Sat, 8/22/09, Chris Tessaglia-Hymes  wrote:

From: Chris Tessaglia-Hymes 
Subject: Re: [nfc-l] Engineers - chime in? Adaptive Noise Cancellation
To: "nfc-l@cornell.edu" 
Date: Saturday, August 22, 2009, 1:00 AM




  
Okay, last post for the night



The more I read about this, the more and more it sounds really cool.



So, you software and hardware engineer people out there - what do you
think? Can it work to better clean up night flight call data
collection? Heck, this could get you closer to that 90-95% positive
detection figure we'd all like to see.



http://plaza.ufl.edu/badavis/EEL6502_Project_1.html



Sincerely,

Chris T-H



Chris Tessaglia-Hymes wrote:

  
  
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
 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
  
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 he

Re: [nfc-l] Engineers - chime in? Adaptive Noise Cancellation

2009-08-21 Thread Chris Tessaglia-Hymes 
Okay, last post for the night

The more I read about this, the more and more it sounds really cool.

So, you software and hardware engineer people out there - what do you 
think? Can it work to better clean up night flight call data collection? 
Heck, this could get you closer to that 90-95% positive detection figure 
we'd all like to see.

http://plaza.ufl.edu/badavis/EEL6502_Project_1.html

Sincerely,
Chris T-H

Chris Tessaglia-Hymes wrote:
> 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 
>>  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  
> 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
>> ejoh...@lsu.edu
>>
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>
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>>>
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>