4 ms·

That will be an interesting task to deal with solving the location of multiple events that may overlap. Over 7km, you will have delays of 10s or so which makes

That will be an interesting task to deal with solving the location of multiple events that may overlap. Over 7km, you will have delays of 10s or so which makes it quite possible that multiple explosions within that window will need disambiguation in the sound record. There should be a parsimony principle that would apply. Very cool project and fun things to work on related to it.

hcfman 3y ago
Indeed Ted! That part is going to be challenging. But not too challenging I think because the number of nodes that will be relevant will be limited and finite. Even brute force solving would work I think. Many nodes will be instantly ruled out because the time differences will be too great to be viable. That's going to be a lot of fun. But I'm sure that when that part arrives where will be plenty of smart people willing to offer directions. Till that time, I have a collaborator in America helping with gathering gunshot sounds and I have intentions to make a matcher that also determines the start time of the event accurately enough to be used for the next stage, to feed into the solver that does the localization. I expect I'll be able to model this to some extent on the way that birdnet from Cornell University works, except that's just identifying a bird and not trying to find with high accuracy the start time of the event. But ultimately that part comes down to generating spectragrams and doing object detection on the spectragram image. Even YoloV6, which should be more accurate than resnet as used in birdnet, can run a nano version of this object detect quite quickly on a Raspberry Pi. It should be possible to make this part within a year. Doing localizations by hand I once heard one that localized to the middle of a car park over 3km away. I drove there and could still smell the sulpher. Also, only in that carpark, not in an adjacent carpark. This suggests that accuracy could well have been within a 40-50m diameter. Amazing! I also tested this with an ultrasonic mic. I could see signatures of small critters that were likely mice as we had chickens at the time. I would need a bunch of ultrasonic mics and an rtk GNSS system to do testing but I expect it might accurate enough in a very small area to determine where rodents are calling from. I'd like to develop this solution with a mind to extending it's use more generically so that it could be used for species surveys in bioacoustic research.

hcfman 3y ago

Indeed Ted! That part is going to be challenging. But not too challenging I think because the number of nodes that will be relevant will be limited and finite. Even brute force solving would work I think. Many nodes will be instantly ruled out because the time differences will be too great to be viable. That's going to be a lot of fun. But I'm sure that when that part arrives where will be plenty of smart people willing to offer directions. Till that time, I have a collaborator in America helping with gathering gunshot sounds and I have intentions to make a matcher that also determines the start time of the event accurately enough to be used for the next stage, to feed into the solver that does the localization. I expect I'll be able to model this to some extent on the way that birdnet from Cornell University works, except that's just identifying a bird and not trying to find with high accuracy the start time of the event. But ultimately that part comes down to generating spectragrams and doing object detection on the spectragram image. Even YoloV6, which should be more accurate than resnet as used in birdnet, can run a nano version of this object detect quite quickly on a Raspberry Pi. It should be possible to make this part within a year. Doing localizations by hand I once heard one that localized to the middle of a car park over 3km away. I drove there and could still smell the sulpher. Also, only in that carpark, not in an adjacent carpark. This suggests that accuracy could well have been within a 40-50m diameter. Amazing! I also tested this with an ultrasonic mic. I could see signatures of small critters that were likely mice as we had chickens at the time. I would need a bunch of ultrasonic mics and an rtk GNSS system to do testing but I expect it might accurate enough in a very small area to determine where rodents are calling from. I'd like to develop this solution with a mind to extending it's use more generically so that it could be used for species surveys in bioacoustic research.