supplierdeeply

Green pixels Canon D20

  • 24 Replies
  • 3588 Views
Green pixels Canon D20
« on: 06 / September / 2015, 09:53:56 »
Advertisements
I have been using CHDK for years on Canon SX40 and D20 without any problems! Simply amazing software! :D
Recently I have been getting green pixels in my dng images from D20. They are not visible in the jpg-images. I have tried creating a new badpixel.bin file several times but that does not help.
I must be doing something wrong…  :P
CHDK 4037

Re: Green pixels Canon D20
« Reply #1 on: 06 / September / 2015, 10:30:13 »
Which version of DNG did you select in the CHDK menu?.  Only 1.1 does bad pixel correction in the camera.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Green pixels Canon D20
« Reply #2 on: 06 / September / 2015, 10:39:15 »
Which version of DNG did you select in the CHDK menu?.  Only 1.1 does bad pixel correction in the camera.

Whops! I have selected 1.3 thinking that that newer is better! :P
Will immediately try 1.1!
Thanks.
BTW, it there an other way of doing bad pixel correction that is better?

*

Offline reyalp

  • ******
  • 11339
Re: Green pixels Canon D20
« Reply #3 on: 06 / September / 2015, 15:07:04 »
Whops! I have selected 1.3 thinking that that newer is better! :P
It is, if your raw software fully supports DNG 1.3 bad pixel handling ;) Unfortunately, except for Adobe products most software doesn't.
Quote
BTW, it there an other way of doing bad pixel correction that is better?
It depends on what software you use. If you can tell your software to fix 0 valued pixels, it will probably do a better job than the in camera badpixel.
Don't forget what the H stands for.


Re: Green pixels Canon D20
« Reply #4 on: 06 / September / 2015, 15:14:59 »
It depends on what software you use. If you can tell your software to fix 0 valued pixels, it will probably do a better job than the in camera badpixel.

Thanks! Very interesting!
I use Photoshop CC 2015, can it somehow fix 0 valued pixels?

*

Offline reyalp

  • ******
  • 11339
Re: Green pixels Canon D20
« Reply #5 on: 06 / September / 2015, 15:54:10 »
It depends on what software you use. If you can tell your software to fix 0 valued pixels, it will probably do a better job than the in camera badpixel.

Thanks! Very interesting!
I use Photoshop CC 2015, can it somehow fix 0 valued pixels?
I don't have photoshop so I don't know. Disappointing Adobe doesn't do the right thing with their own file format  >:(

In the past IIRC you needed a plugin to open DNG at all (adobe camera raw?) but google suggests that's not the case any more. I'd expect lightroom to do the right thing.
Don't forget what the H stands for.

Re: Green pixels Canon D20
« Reply #6 on: 06 / September / 2015, 16:43:22 »
I don't have photoshop so I don't know. Disappointing Adobe doesn't do the right thing with their own file format  >:(

In the past IIRC you needed a plugin to open DNG at all (adobe camera raw?) but google suggests that's not the case any more. I'd expect lightroom to do the right thing.

Thanks reyalp! I guess I'll have settle for DNG 1.1 since getting 1.3 to work seems a bit too complicated and technical for me. :P

*

Offline philmoz

  • *****
  • 3070
    • Photos
Re: Green pixels Canon D20
« Reply #7 on: 06 / September / 2015, 16:53:24 »
It depends on what software you use. If you can tell your software to fix 0 valued pixels, it will probably do a better job than the in camera badpixel.

Thanks! Very interesting!
I use Photoshop CC 2015, can it somehow fix 0 valued pixels?

That should happen automatically - I just tried a quick test and PC CC (2015.0.1) correctly removed the bad pixels from the DNG file.

Can you upload your DNG to a file share site (e.g. dropbox, google drive, etc) and post the link here.

Phil.
CHDK ports:
  sx30is (1.00c, 1.00h, 1.00l, 1.00n & 1.00p)
  g12 (1.00c, 1.00e, 1.00f & 1.00g)
  sx130is (1.01d & 1.01f)
  ixus310hs (1.00a & 1.01a)
  sx40hs (1.00d, 1.00g & 1.00i)
  g1x (1.00e, 1.00f & 1.00g)


Re: Green pixels Canon D20
« Reply #8 on: 06 / September / 2015, 17:09:22 »

That should happen automatically - I just tried a quick test and PC CC (2015.0.1) correctly removed the bad pixels from the DNG file.

Can you upload your DNG to a file share site (e.g. dropbox, google drive, etc) and post the link here.

Phil.

Unfortunately I deleted the image from my kitchen but here is another image from yesterday. Lots of green pixels and even some blue ones in the orange koi carp  :) The file is DNG 1.3
https://dl.dropboxusercontent.com/u/66272586/CRW_6315.DNG
Very interesting to see if it works for you. I also have PS 2015.0.1

*

Offline reyalp

  • ******
  • 11339
Re: Green pixels Canon D20
« Reply #9 on: 06 / September / 2015, 18:05:27 »
Unfortunately I deleted the image from my kitchen but here is another image from yesterday. Lots of green pixels and even some blue ones in the orange koi carp  :) The file is DNG 1.3
https://dl.dropboxusercontent.com/u/66272586/CRW_6315.DNG
Very interesting to see if it works for you. I also have PS 2015.0.1
Interesting. Adobe dng_validate -tif seems to take care of the badpixels. It does give some warnings about the active area:
Code: [Select]
*** Warning: Too little padding on left edge of CFA image (possible interpolation artifacts) ***
*** Warning: Too little padding on top edge of CFA image (possible interpolation artifacts) ***
*** Warning: Too little padding on right edge of CFA image (possible interpolation artifacts) ***
*** Warning: Too little padding on bottom edge of CFA image (possible interpolation artifacts) ***
but I wouldn't expect this to affect bad pixel processing.

It looks like you have default crop (DNG Crop Size in the CHDK menu) set to "Full". This means that the large black areas on the top/left will be included, as well as somewhat darker borders that contain image data. I'd generally suggest using "active" or "jpeg" except for debugging, but again wouldn't expect this to affect badpixel handling.

There seem to be a large number of pixels with value 2 rather than 0. There are also a lot with value slightly less than blacklevel starting around 90), but AFAIK this is common.

Using chdkptp
Code: [Select]
___> dnghist -min=0 -max=128
0 28858
1 64
2 12176
... zero ...
90 0
91 1
92 0
... zero ...
96 0
97 1
98 0
99 0
100 0
101 1
102 4
103 1
104 3
105 4
106 5
107 9
108 15
109 10
110 21
111 23
112 28
113 46
114 34
115 68
116 83
117 139
118 155
119 217
120 321
121 555
122 1226
123 3259
124 8535
125 20832
126 40183
127 62999
128 75547

Edit: all the pixels with values 1-2 seem to be very close to the right edge (x=4164-4167), so they shouldn't be the cause of the problem.
« Last Edit: 06 / September / 2015, 18:10:53 by reyalp »
Don't forget what the H stands for.

 

Related Topics