badpixel.lua never works on G7 - RAW Shooting and Processing - CHDK Forum
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badpixel.lua never works on G7

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Offline mcgd

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badpixel.lua never works on G7
« on: 26 / January / 2009, 06:55:25 »
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Hi,

I have tried over and over to run badpixel.lua to make me a badpixel.bin file, but it always just says "Try this script again".  From the code it seems that this happens when it checks for bad pixels twice and gets a different count each time.  I'm not clear if the camera needs to be in complete darkness when I run this?  I tried running it with the camera shut in a drawer but it still didn't work.  Am I doing something wrong?

I tried just taking the bad_tmp.bin and just renaming it to badpixel.bin, but the resulting DNG files have at least one "stuck" looking pixel.
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Offline mcgd

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Re: badpixel.lua never works on G7
« Reply #1 on: 02 / February / 2009, 04:27:17 »
Can anyone give me any advice on this?  I have printed out the difference between the two bad pixel counts, and got as low as 5 and high as around 200.  Is this normal, or is there something wrong with the camera?  Normal shots don't seem to have stuck pixels.

I'm also not sure about the best way to run badpixel.lua.  Should the camera be in the dark, or should I be in bright light - does it matter?  It always seems to take maybe 15 second exposures regardless of what light it's in.
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Offline fudgey

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Re: badpixel.lua never works on G7
« Reply #2 on: 02 / February / 2009, 14:51:32 »
Quote from: mcgd on 02 / February / 2009, 04:27:17
Can anyone give me any advice on this?  I have printed out the difference between the two bad pixel counts, and got as low as 5 and high as around 200.  Is this normal, or is there something wrong with the camera?  Normal shots don't seem to have stuck pixels.

Both 5 and 200 seem very low. Should probably be thousands? Or are G series sensors that much different?

Quote from: mcgd on 02 / February / 2009, 04:27:17
I'm also not sure about the best way to run badpixel.lua.  Should the camera be in the dark, or should I be in bright light - does it matter?  It always seems to take maybe 15 second exposures regardless of what light it's in.

I thought lighting had nothing to do with this?
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Offline mcgd

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Re: badpixel.lua never works on G7
« Reply #3 on: 03 / February / 2009, 03:48:09 »
5 and 200 were the differences between the two times it got bad pixels.  The script gets the bad pixels twice, and finds out how many there were.  It seems that when it gets a list of bad pixels maybe 30 seconds apart, the count of bad pixels is between 5 and 200 different each time.  This seems strange.

I'm not sure whether lighting affects it or not - I can't find any documentation about that.  I was wondering if anyone knows whether lighting affects it.  I'm not sure why it takes actual photos each time.
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Offline barret

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Re: badpixel.lua never works on G7
« Reply #4 on: 03 / February / 2009, 04:05:09 »
i think light does not matter, if this is done through standard dark frame procedure, in which shutter is closed, so no light enter camera. if it is done through some other method then situation might be different.
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Offline Davide

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Re: badpixel.lua never works on G7
« Reply #5 on: 06 / February / 2009, 07:46:14 »
Light does matter for me, but my results are stable.

If you are interested, I have posted about it:
http://chdk.setepontos.com/index.php/topic,3114.0.html

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Offline fe50

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Re: badpixel.lua never works on G7
« Reply #6 on: 07 / February / 2009, 08:42:08 »
See CHDK wikia: Badpixel removal.

badpixel.lua generates the badpixel.bin needed for DNG creation, it depends on the badpixel list(s) in the Canon firmware.
On some cameras there are 2 (or maybe more ?) such lists for different exposure times...

Quote
    * Try several RAW files to obtain stable result (approximate shooting conditions: minimal ISO, exposure time ~1/10s).
    * Some cameras have two defect pixel lists, which are switched at exposure time ~1/25s. Use the list with maximum (but stable) defect pixel count, otherwise you can see multiple black points on image in some RAW convertors.
    * For DNG RAW shooting place the file here: \CHDK\badpixel.bin
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Offline mcgd

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Re: badpixel.lua never works on G7
« Reply #7 on: 09 / February / 2009, 08:21:06 »
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Light does matter for me, but my results are stable
Interesting that you got only two different values.  I seem to get different values every photo - e.g.  12118, 11531, taking the picture twice.  Did it again and got 11533, 11540.  Then 11562, 11542, than 11548, 11540.  Apart from the first one, they are all around the same mark, but always slightly different.
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Offline Davide

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Re: badpixel.lua never works on G7
« Reply #8 on: 28 / April / 2009, 18:06:09 »
Quote from: mcgd on 09 / February / 2009, 08:21:06
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Light does matter for me, but my results are stable
Interesting that you got only two different values.  I seem to get different values every photo - e.g.  12118, 11531, taking the picture twice.  Did it again and got 11533, 11540.  Then 11562, 11542, than 11548, 11540.  Apart from the first one, they are all around the same mark, but always slightly different.
I have tested it more thoroughly. Actually it gives me 3 different values.

1/30 or faster exposure time-> 8785
1/25 - 1/8 -> 2715
1/6 or slower -> 1483

I'm now using the bigger value with success.
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