Fixed pattern noise subtraction test

[sunyata]

These are the results of trying to isolate fixed pattern noise from a noisy signal and then subtract if from footage. Brad Bell was cool enough to record some 4k noise from the BMPC for me. 

 

This requires capturing noise from the camera you're trying to de-noise. The pattern seems to be pretty fixed over time, i.e. it was working with older footage from the same camera.

 

Noise was shot with lens cap on at 600 iso, 4k, 10bit, prores, 25fps, film gamma, and only 150 frames. Nuke was used to average all 150 4k frames into a single image. 

 

A subtract was done on the clips in the NLE using the produced 4k 10bit dpx file. The FPN image was de-saturated and levels were adjusted to knock out the white spots and leave the mids. This was done with an expand and clamp on the graphic. Dots seemed to line up perfectly, even after resizing and downloading re-compressed footage, so not ideal conditions. 

 

 

This technique should work on any FPN but the BMPC is one of the clearest. Still plan to test on scenery and live action but for now, this is what I've been able to get. Hope it helps someone out in Black Magic firmware limbo.