Bad Pixel Removal Options?

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    Bad Pixel Removal Options?
    « on: 30 / March / 2009, 17:03:10 »
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    I have been reviewing RAW Parameters.

    One that interests me is "bad pixel removal" but have not found a good explanation of the on options of Average and RAWconv in either the CHDK Wiki (only found http://chdk.wikia.com/wiki/CHDK_firmware_usage/MoreBest#Bad_Pixel_Removal  but this does not seem to be up to date) or forum.

    Hopefully someone has been using it and has suggestions concerning these bad pixel removal options.

    Thanks

    Steve

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    Offline fe50

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    Re: Bad Pixel Removal Options?
    « Reply #1 on: 31 / March / 2009, 02:52:43 »
    One that interests me is "bad pixel removal" but have not found a good explanation of the on options of Average and RAWconv

    "Average" - CHDK makes bad pixel interpolation.
    "RAWconv" - CHDK only marks this pixel as bad for interpolation in RAW converter (internal or external).
    This option is ignored in DNG mode (in DNG mode bad pixels are averaged by CHDK always).
    Quote
    What factors would go into my choice of one or the other?
    You can compare bad pixel removal quality in both modes (IMO," RAWConv" mode is preferred, because CHDK interpolation is very unsophisticated).

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    Re: Bad Pixel Removal Options?
    « Reply #2 on: 01 / April / 2009, 16:48:20 »
    Hi fe50,

    Thanks again for your tips and comments!

    Have you or anyone else posted test photos made with RAWconv and no bad pixel removal so we can see how much difference it makes?

    I did find lrossel's photos dummybadpixel.jpg (35.63 KB, 774x453 - viewed 59 times.) and Realbadpixel.jpg (35.25 KB, 773x454 - viewed 65 times.)  http://chdk.setepontos.com/index.php/topic,156.msg24317.html#msg24317  "I made a comparison between shots taken with my A720IS using the dummy badpixel.bin file attached by Ewavr in his reply #42 and a real one created with the show_bad_b.exe utility."  Because of the date difference when this was posted (15 / November / 2008) and now, I do not know if the software used is even current.

    Steve
    « Last Edit: 01 / April / 2009, 17:44:02 by StevenD »

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    Offline Sess

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    Re: Bad Pixel Removal Options?
    « Reply #3 on: 04 / April / 2009, 21:13:03 »
    If you use RAWconv mode, does it still remove bad pixels from JPGs?

    At http://chdk.wikia.com/wiki/CHDK/MoreBest#Bad_Pixel_Removal, it says:
    "if the "Average" behavior is selected, it will use the number after the "=" (let's call it "bias") to determine the pixel value: value=(value-bias)*((MAXVAL+bias)/MAXVAL) * (MAXVAL-bias) +  nearest_neighbors_average * bias."
    Does this mean that the number after the '=' in the badpixel file will affect how strongly the pixel is averaged out?

    And what's the difference between these:
    show_bad.eve
    show_bad_b.exe (I think this one might be for manually creating a badpixel.bin...)
    show_stat.exe

    Also, at http://chdk.wikia.com/wiki/CHDK/MoreBest#Bad_Pixel_Removal it points to show_bad_stat.zip but that doesn't seem to exist. In fact, when you click on it some weird stuff happens: http://ewavr.nm.ru/chdk/show_bad_stat.zip I think Ewavr should check on where his host points people to when they click broken links.
    « Last Edit: 04 / April / 2009, 22:31:24 by Sess »


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    Offline fe50

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    Re: Bad Pixel Removal Options?
    « Reply #4 on: 05 / April / 2009, 05:55:41 »
    If you use RAWconv mode, does it still remove bad pixels from JPGs?
    At http://chdk.wikia.com/wiki/CHDK/MoreBest#Bad_Pixel_Removal, it says:
    "if the "Average" behavior is selected, it will use the number after the "=" (let's call it "bias") to determine the pixel value: value=(value-bias)*((MAXVAL+bias)/MAXVAL) * (MAXVAL-bias) +  nearest_neighbors_average * bias."
    Does this mean that the number after the '=' in the badpixel file will affect how strongly the pixel is averaged out?

    Since this version of the bad pixel removal is not in the current CHDK (it's a patch provided by LJL), you can either try to adapt the sources to the current CHDK build & compile a test version to test it...

    Quote
    And what's the difference between these:
    show_bad.eve
    show_bad_b.exe (I think this one might be for manually creating a badpixel.bin...)
    show_stat.exe

    ...see also http://chdk.wikia.com/wiki/Badpixel_removal

    show_bad.exe -> for "general" bad pixel removal (http://chdk.wikia.com/wiki/CHDK_firmware_usage/AllBest#Hot-Pixel_Removal_.28Build_100-16_and_later.29 )
    show_bad_b.exe -> for DNG support, creat a special badpixel.bin file with the badpixels known by the original software (http://chdk.wikia.com/wiki/Badpixel_removal#show_bad_b )
    show_bad_stat.exe -> used for LJL's patch, to show the luminosity values... (http://chdk.wikia.com/wiki/CHDK_firmware_usage/MoreBest#Bad_Pixel_Removal )

    Quote
    Also, at http://chdk.wikia.com/wiki/CHDK/MoreBest#Bad_Pixel_Removal it points to show_bad_stat.zip but that doesn't seem to exist. In fact, when you click on it some weird stuff happens: http://ewavr.nm.ru/chdk/show_bad_stat.zip I think Ewavr should check on where his host points people to when they click broken links.

    That's a problem of the provider / hoster...
    You'll find most of such CHDK related tools also here: CHDKsoft drop, i've updated the link you mentioned to http://drop.io/chdksoft/asset/show-bad-stat-zip.

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    Offline Sess

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    Re: Bad Pixel Removal Options?
    « Reply #5 on: 05 / April / 2009, 08:38:51 »
    Ah, thanks for the correct link. As for my first question, I pointed to http://chdk.wikia.com/wiki/CHDK/MoreBest#Bad_Pixel_Removal only because it gave descriptions of Average and RAWconv. However my question is actually about the version of badpixel removal that comes in AllBest builds, not LjL's patch.

    For the latest version of AllBest, on the RAW settings page, you can choose Off/Average/RAWconv. You said:
    "Average - CHDK makes bad pixel interpolation.
    RAWconv - CHDK only marks this pixel as bad for interpolation in RAW converter (internal or external). This option is ignored in DNG mode (in DNG mode bad pixels are averaged by CHDK always)."

    So for AllBest, does Average ignore the numbers after '=' or does it use them to control how strongly the pixel is removed?

    For RAWconv, you said that it only marks pixels bad on the RAW for interpolation later. Does this mean that the JPGs are not cleaned? Or if they are in fact cleaned, will they be cleaned differently than the Average mode?

    Finally, what if it is in DNG mode? I know the DNG itself will be averaged (as you said), but what about the JPG? Will it still be affected by the Average/RAWconv setting?

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    Offline Sess

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    Re: Bad Pixel Removal Options?
    « Reply #6 on: 03 / May / 2009, 17:41:25 »
    Why do my questions always seem to kill a thread?

     

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