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Alpha and Color Values in Textures / camera tracking BG subtraction

Hey All!

after a while i started concerning myself with Cameratracking again… i am now trying to build a kind of “adaptive” background subtraction, like the freeframe trautner node, just slower… it will come in handy when using with a FTIR screen over a long time, eliminating bright spots caused by dirt on the screen as well as in camera tracking in unstable lighting conditions…

i am using the regular background subtraction shader with a texture generated from the live camera input that paints over a renderer that is not being cleared. i use a quad with white color and an alpha value of 10% (0.1).

problem is, this is still adapting too fast. when i lower the alpha, the results are fine, except that dark pixels seem not to be replaced with bright pixels coming in the next frames… they are just not painted over when using an alpha value of 0.01… is there anything i can do about that? i’d like the adaption to run smoothly, a workaround would be to paint a new image every 20 frames or so, but the steps are very well noticeable then…

cheers and thanks in advance!
jens

i dont see why alpha values less than 0.1 shouldnt work. (1/255 would be a plausible lower bound) did you try using a high dynamic range renderer (with a pixelformat something like R16G16B16A16?)