So you want to do some infrared (IR) tracking onstage but there’s too much ambient IR in the space for your blob detection to work reliably? You need to only light up your subject? Or only your backdrop?
Never fear. Our bespoke IR emitter solution is here, ready to cancel out your ambient IR.
It’s an Arduino plugged into a basic IR emitter from Amazon. With a network shield, the Arduino/emitter flashes at 60Hz in sync with our openFrameworks app and the camera, capturing at 120Hz. Hopefully you can see where this is going…
- Sixty times per second we receive two frames from the camera
- One frame with ambient IR On and the emitter IR On
- One frame with ambient IR On and the emitter IR Off
- Subtract one from the other and we’re left with a frame containing only the emitter IR, NO ambient IR
- Run computer vision algorithm on resulting frame using only emitter IR
I wouldn’t try this with DMX, as the IR flashing needs to be timed to the millisecond. So we multicast a sync message on the LAN to the Arduino. If anyone knows of an off-the-shelf IR emitter product that’ll do something like this with millisecond responsiveness, please let us know!