John, > > >Thanks for posting this. I've thought about doing this, but had not gotten >around to trying it. I'll give it a try when I have a chance. > >Laura > > > > > > >>________________________________ >> From: John Kearney <[email protected]> >>To: [email protected] >>Sent: Monday, October 7, 2013 3:41 PM >>Subject: [nfc-l] More on processing night flight calls >> >> >> >>Hi All, >>As a follow-up to Debbie’s question about processing night flight calls with >>Raven Pro, I recall that Laura Gooch recently raised the dilemma of the great >>amount of work required in processing lower frequency, thrush-like calls, due >>to traffic noise. I have a problem with ambient noise from frequent and >>sustained rain and wind at one my listening sites. It is not unusual to get >>30 to 80 thousand detections in a single night. So I’ve been experimenting >>with bandwidth filters to filter out some of the wind and rain noise, and >>have had some considerable success. For the low frequency band, I’ve been >>using a minimum bandwidth filter of 100 Hz and a maximum of 500 Hz with >>energy percentile of 40%. This has reduced my detections by as much as >>two-thirds or more with little change in the number of true positives. For >>exceptionally bad weather, it is necessary to increase the energy percentile >>to 50 or 60%. This will pull out the “loudest calls” and then you can go back and do a more specific search for calls in the time period where these calls were detected. >>Has anyone else used bandwidth filters in this way and would you willing to >>share your findings? >>Thanks, >>John >> >>-- >>NFC-L List Info: >>Welcome and Basics >>Rules and Information >>Subscribe, Configuration and Leave >>Archives: >>The Mail Archive >>Surfbirds >>BirdingOnThe.Net >>Please submit your observations to eBird! >>-- >> >> > > --
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