Author Topic: Viewing CFA Directly  (Read 2962 times)

Offline aworonow

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Viewing CFA Directly
« on: 2014 November 29 12:49:59 »
Hello,
  When I opened a .CR2 file and zoom way in, I expected to see the CFA pattern with pure red, green, and blue pixels of varying intensity. But I do not. There are red squares (pixel representations I suppose) next to other red ones, greens squares next to greens, and, even white squares, etc. This leads to two questions: 1) is there a way to directly view the representations of single pixel values in the CFA without some processing affecting the display for these? 2) are operations like stacking actually done at the CFA-pattern level rather than at a level closer to what zooming displays?
  The reason I ask, is I am about to begin looking into an alternative processing train for OSC and DSLR images and would like to see how the procedures change the true pixel intensities, one-by-one, rather than how they change what becomes displayed. If this quick-look appears promising, I would, of course, share. But that is premature right now.

Thanks, Alex Woronow

Offline Carlos Milovic

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Re: Viewing CFA Directly
« Reply #1 on: 2014 November 29 13:05:07 »
Calibration is done with bayered data. The CFA raw data is loaded as a grayscale single-channel image. You have to debayer for aligment (registration) and integration, or make use of the drizzle algorithm to combine the cfa data into a final color composite. After that, everything is performed always on debayered data.

To change the behavior when you open cr2 files, use the FormatExplorer, and then edit the canon crw format.


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Offline pfile

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Re: Viewing CFA Directly
« Reply #2 on: 2014 November 29 13:10:38 »
there are 2 ways to represent bayer data. one is in a mono file (raw bayer CFA). the other is in a 3-plane file (raw bayer). you can control what PI does when opening a CR2 in the file explorer. double click DSLR_RAW and you will see the settings.

in the screenshot, left is a CR2 file opened with raw bayer CFA, right is raw bayer RGB.


Offline georg.viehoever

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Re: Viewing CFA Directly
« Reply #3 on: 2014 December 03 01:24:12 »
...when opening a CR2 in the file explorer. double click DSLR_RAW and you will see the settings...
You probably mean the FormatExplorer.
Georg
Georg (6 inch Newton, unmodified Canon EOS40D+80D, unguided EQ5 mount)

Offline pfile

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Re: Viewing CFA Directly
« Reply #4 on: 2014 December 03 08:58:04 »
sorry, yes. thanks georg.