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: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.NortheastBirding.com/NFC-L_SubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NFC-L 3) http://birdingonthe.net/mailinglists/NFCL.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
