Doom9's Forum - View Single Post - deflicker approach for removing medium-speed brightness changes?

jbeale · 25th June 2010, 00:46

I have some camcorder footage of a dance performance in which the camera's AGC circuit controlling exposure causes the background brightness to pump down and up whenever someone in a light-colored dress passes through brightest part of the stage. The time scale of the brightness fluctuation is about 20 to 40 frames. It is visually bothersome (to me at least) and I'm sure it hurts compression efficiency also, so I'd like to fix this if I can.

The existing de-flicker filters seem designed to remove pixel noise, or deal with brightness changes of only a few frames in duration. Any advice out there for this particular problem? I also need to restrict the area examined to find the average background brightness that I want to stabilize, otherwise (I assume) the filter will just end up copying what the camera AGC did. I might even want to average the whole frame except for the brightest 1/3 of the pixels in the frame, for example.

Are there de-flicker filters that cover any number of frames, and accept an arbitrary mask frame to use for the average background level?

25th June 2010, 00:46	#1 \| Link
jbeale Registered User Join Date: May 2003 Posts: 31	deflicker approach for removing medium-speed brightness changes? I have some camcorder footage of a dance performance in which the camera's AGC circuit controlling exposure causes the background brightness to pump down and up whenever someone in a light-colored dress passes through brightest part of the stage. The time scale of the brightness fluctuation is about 20 to 40 frames. It is visually bothersome (to me at least) and I'm sure it hurts compression efficiency also, so I'd like to fix this if I can. The existing de-flicker filters seem designed to remove pixel noise, or deal with brightness changes of only a few frames in duration. Any advice out there for this particular problem? I also need to restrict the area examined to find the average background brightness that I want to stabilize, otherwise (I assume) the filter will just end up copying what the camera AGC did. I might even want to average the whole frame except for the brightest 1/3 of the pixels in the frame, for example. Are there de-flicker filters that cover any number of frames, and accept an arbitrary mask frame to use for the average background level? Last edited by Guest; 25th June 2010 at 02:45. Reason: 12