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Bad Pixel Removal for JPG/JPEG - What Worked for Me

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Bad Pixel Removal for JPG/JPEG - What Worked for Me
« on: 19 / January / 2011, 02:58:19 »
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After much trial and error, these are the steps I used to get bad pixels removed from JPGs on my SD780 build 1050:

1) Switch camera over to Raw mode (CHDK Menu \ Raw Parameters \ Save Raw)
2) While still in the RAW menu, enable Bad pixel removal (I used "Average.").  Note:  I believe this is needed for bad pixel removal in JPGs, not just RAW.
3) Switch camera to a lower ISO setting, I used 200
4) Switch camera to a slower shutter speed, I used 5sec
5) Take a few shots in no light.  Be sure to half press and wait for the shooting screen, I noticed that if you full press too quickly certain features don't work.
6) You should have some raw files, I saw a few CR2 files.
7) Use the attached CMD files that will create the badpixel.txt file.  Simply drag your RAW file over the cmd you wish to use to create the file.  I believe the numbers are luminocity thresholds, I ended up using 128 as going lower seemed to create a larger file which may not work during bad pixel removal (file size limit?)
   Note: I read that some people recommended Unix line breaks (\n vs \r\n ), the file created is dos (\r\n) and seemed to work fine without modification
8) Copy the badpixel.txt as both "badpixel" no extension and "badpixel.txt" into the CHDK folder.  I believe only one file is necessary but I didn't want to waste time so I created both files.

You should be good to go.  You should take some pictures in the dark with regular JPG and compare against older photos to verify that the bad pixels were indeed removed.

Good luck!

showbad.zip alternative link:
http://rapidshare.com/files/443361100/ShowBad.rar

 

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