[jitter] Re: Re: 2d Position Tracking in Low Light

Thanks again yair for your detailed and helpful response. I've so far built a small array of LEDs and attached them to the performer and done some tests with jitter. 

cv.jit.track does a pretty good job tracking the LED, but still I wonder if it would work better in a situation where the stage was bathed in IR light from a large IR source and the performer was wearing reflective tape. I wonder this becuase thie cv.jit.track optical flow algorithm seems to track SHAPES, and a single point in the dark from a few leds forms more of a POINT than a recognizable shape. 

I recall your warning about CCTV type IR LED arrays often used for security and how they can have a too narrow angle. But then I saw this:

http://www.columbussupply.com/products/?productid=669&price=1278

Not cheap but claims a 360 degree IR light visible from long distance ($120). 

My main problem though has been getting the LEDs bright enough to really be visible from a distance when mounted on the performer. I've tried a ping pong ball, but it was too opaque for my weak IR LEDs to illuminate.

I am using these IR LEDs

http://www.mouser.com/Search/ProductDetail.aspx?qs=vs%252bWWTB4QKYLfZ6uf%2fu%252b0Q%3d%3d

They have a beam angle of 50 degrees (not bad) and a wavelength of 940nm. If anyone can recommend a brighter LED, or any techniques to improve their output it would be appreciated. Right now I am using 4 of them with a nine volt battery stepped down with a 150 ohm resistor. Not very bright at all.

Again thanks for any help.