I think the use of [threshold~] is limiting you to block resolution. Audio to do correlation will give you a theoretical resolution much better than one block, at half the sampling rate, 0.015m (one and a half centimeters) for 44kHz.(?) Assuming that the mics are identical, in phase etc.
[snapshot~] seems a better choice than [threshold~] because it gives you the instantaneous vaue of a sample. But I'm not quite sure how best to use it in this context.
It depends on the source, if its an impulse or if it's a periodic wave, for which correlation approach. I was reading this interesting one recently and wondered if anyone tried it
- Clip the two signals - i.e. amplify and saturate so the signals become a
series of 1s and 0s.
- XOR the result. You will use this result "X" in two ways:
- Integrate X to get Y
- Measure the variance of Y
When the variance of Y approaches zero, there is similarity. Y itself is a measure of time shift between the signals. This works for things like sinusoids. Fred
If it's for delocalisation/positioning of emitters where you get to decide what the sound is (and choose a nice ultrasonic sine wave) then it seems potentialy fast because it can be crudely sampled and carried out as logic.
On Sat, 23 Jun 2007 22:12:53 +0200 Chris chris@proquariat.de wrote:
Hi, I made a patch to locate the position of a sound source between two microphones, which looks like this: [adc~] | | | [threshold~ 0.2 100] | | [threshold~ 0.2 100] | | [delay 10] | | [timer]
So a number of 10ms means that the source is exactly between the two microphones. This patch works kind of reliable and accurate. But I was wondering if there is a better possibility with higher resolution? At the moment I can distinguish the position with an accuracy of 1.333 ms, means I get about 12 different values out of my tube.
Has anyone an idea how I can get more precise readings? I thought about comparing the amplitudes of the two waves I get, but I have no idea how to do this or if this would be more exact.
Thanks for any help, Chris
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