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Problems with the raws interpretated by Python/dcraw

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Problems with the raws interpretated by Python/dcraw
« on: 06 / May / 2021, 09:49:00 »
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Hi!

Days ago being work in a process based in Python with the manipulation of the raws but I have a problem. I have two ways to work. The first is in the same Python with rawpy library, that's based in dcraw and work with numpy native, but the images which the ISO is high are process to much and the photo becomes white. The second way is with dcraw directly but the result is similar, the photos that taked in a "good" conditions creates a correct ppm but when the image is dark the results of the process turns the result in a soup of white noise that was not at the raw photo. The JPG directs of the camera are good (If the image are dark, the result is dark not a white noise).

The raws are DNG, I don't know if this is part of the problem.

So, the only thing I want is extract the matrix of pixels and work with them without this problems.

Anybody have an idea?

Thank you so much!

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Offline SX720

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Re: Problems with the raws interpretated by Python/dcraw
« Reply #1 on: 25 / May / 2021, 22:53:54 »
You are going to need to supply more information such as what arguments you are passing to dcraw and perhaps a sample of a DNG.

Dcraw by default makes dark images brighter. Please use the -W option if you are not already. Here is the description from the dcraw help:
Code: [Select]
-W        Don't automatically brighten the image
« Last Edit: 25 / May / 2021, 22:55:36 by SX720 »

Re: Problems with the raws interpretated by Python/dcraw
« Reply #2 on: 26 / May / 2021, 04:02:11 »
When I was post the coment I being use -c and -w. Anyway I found the same instruction in rawpy (no_auto_bright = True) and I work with it.

Thank you too

 

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