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Author Topic: Monochrome r/g/b images from raw?  (Read 8297 times)

dreed

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Monochrome r/g/b images from raw?
« on: May 03, 2012, 10:32:37 AM »

Are there any software packages that generate monochrome images from just one of the r/g/b channels in a raw file that do not invent extra pixels?

To give you an idea of what I mean, from a 20MP raw file, I'd expect a 5MP "blue" file, a 5MP "red" file and a 10MP "green" file.
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Mark D Segal

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Re: Monochrome r/g/b images from raw?
« Reply #1 on: May 03, 2012, 10:34:47 AM »

As far as I know, there are no "channels" in a raw file. The image needs to be rendered as an RGB image. Then in Photoshop you can go to the Channels palette and work with individual channels.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml

deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #2 on: May 03, 2012, 10:53:59 AM »

Are there any software packages that generate monochrome images from just one of the r/g/b channels in a raw file that do not invent extra pixels?

To give you an idea of what I mean, from a 20MP raw file, I'd expect a 5MP "blue" file, a 5MP "red" file and a 10MP "green" file.


http://www.libraw.org/docs/Samples-LibRaw-eng.html

"...4channnels - splits RAW-file into four separate 16-bit grayscale TIFFs (per RAW channel).
Command line switches:

    -s N selects N-th image from RAW with multiple images
    -g gamma correction (gamma 2.2)
    -A values autoscale by auto-calculated integer factor
    -B turn off black subtraction
    -N no RAW curve

..."
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Mark D Segal

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Re: Monochrome r/g/b images from raw?
« Reply #3 on: May 03, 2012, 10:58:43 AM »

For anyone who has the appetite to get into all that. Fundamentally though, from what I see, it creates (not extracts) TIFF image channels from the raw file.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml

sandymc

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Re: Monochrome r/g/b images from raw?
« Reply #4 on: May 03, 2012, 11:00:14 AM »

Are there any software packages that generate monochrome images from just one of the r/g/b channels in a raw file that do not invent extra pixels?

To give you an idea of what I mean, from a 20MP raw file, I'd expect a 5MP "blue" file, a 5MP "red" file and a 10MP "green" file.


There are few additional options that will show that in various forms:

  • draw with the -D option
  • dng_validate with the -b4 option
  • RawAnalyze
  • RawDigger

Not sure whether any of them generate separate files.

Sandy
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joofa

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Re: Monochrome r/g/b images from raw?
« Reply #5 on: May 03, 2012, 12:20:04 PM »

Are there any software packages that generate monochrome images from just one of the r/g/b channels in a raw file that do not invent extra pixels?

To give you an idea of what I mean, from a 20MP raw file, I'd expect a 5MP "blue" file, a 5MP "red" file and a 10MP "green" file.


I have made a free Photoshop plugin that separates r/g/g/b channels into individual images. It can also display them together in a single image as a Bayer RGGB pattern. You can download it from http://djjoofa.com/download. However, it does not give you a single green image, rather two separate green images coming from two green channels in the Bayer pattern. At this stage it only works on Mac Os 10.6.8 and Photoshop CS3, though.

Joofa
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Joofa
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #6 on: May 03, 2012, 04:34:58 PM »

For anyone who has the appetite to get into all that. Fundamentally though, from what I see, it creates (not extracts) TIFF image channels from the raw file.

it does exactly what OP was asking for... TIFF is a just a container for the raw data extracted from raw files... each file contains one channel (R, G1, B, G2)...

PS: G1 != G2 hence you get 2 files instead of 1 (as OP was hoping for).
« Last Edit: May 03, 2012, 04:36:31 PM by deejjjaaaa »
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Mark D Segal

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Re: Monochrome r/g/b images from raw?
« Reply #7 on: May 03, 2012, 04:56:04 PM »

it does exactly what OP was asking for... TIFF is a just a container for the raw data extracted from raw files... each file contains one channel (R, G1, B, G2)...

PS: G1 != G2 hence you get 2 files instead of 1 (as OP was hoping for).

Do I understand right that you are saying what ends-up in these TIFFs as separated channels are not formed of pixels with bit-depth, or they don't then need to be converted into channels of pixels at a certain bit-depth to be worked with?
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Mark D Segal (formerly MarkDS)
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dreed

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Re: Monochrome r/g/b images from raw?
« Reply #8 on: May 03, 2012, 06:04:15 PM »

There are few additional options that will show that in various forms:

  • draw with the -D option

draw or dcraw? dcraw with -D would give me a full size B&W image, not ... maybe I wasn't driving it right?

Quote
  • dng_validate with the -b4 option

I'm not sure what this was meant to do, but there seems to be no option to dng_analyze (found in the DNG SDK) that allows you to output just a single channel.

Quote
  • RawAnalyze

I tried this but I wasn't at all sure about what I was doing. Similarly, I couldn't work out how to create an image file of just one channel, if that is possible.

Quote
  • RawDigger

Wanted to phone home over the Internet so I uninstalled it. (This means it would not operate unless it could make a connection to some host on the Internet. It's an application for working with photos, not a web browser, so no, it does not get to connect to the Internet.)
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dreed

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Re: Monochrome r/g/b images from raw?
« Reply #9 on: May 03, 2012, 06:06:05 PM »

http://www.libraw.org/docs/Samples-LibRaw-eng.html

"...4channnels - splits RAW-file into four separate 16-bit grayscale TIFFs (per RAW channel).
Command line switches:

    -s N selects N-th image from RAW with multiple images
    -g gamma correction (gamma 2.2)
    -A values autoscale by auto-calculated integer factor
    -B turn off black subtraction
    -N no RAW curve

..."

Windows .exe?
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #10 on: May 03, 2012, 06:18:23 PM »

Windows .exe?

..

http://www.libraw.org/data/LibRaw-0.14.6-Win32.zip

do not ask me how to extract from archive though !
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #11 on: May 03, 2012, 06:20:05 PM »

Wanted to phone home over the Internet so I uninstalled it. (This means it would not operate unless it could make a connection to some host on the Internet. It's an application for working with photos, not a web browser, so no, it does not get to connect to the Internet.)

sure, KGB wants your raws !
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Mark D Segal

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Re: Monochrome r/g/b images from raw?
« Reply #12 on: May 03, 2012, 06:23:27 PM »

Are there any software packages that generate monochrome images from just one of the r/g/b channels in a raw file that do not invent extra pixels?

To give you an idea of what I mean, from a 20MP raw file, I'd expect a 5MP "blue" file, a 5MP "red" file and a 10MP "green" file.


Going back to the OP in light of some of the responses here, it seems to me that the proposed options are rather arcane - in the sense that they require very above average computing skills to work with them. I'm wondering what the purpose of the request is and in that context whether there is a simpler, more conventional solution.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml

deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #13 on: May 03, 2012, 06:23:46 PM »

Do I understand right that you are saying what ends-up in these TIFFs as separated channels are not formed of pixels with bit-depth, or they don't then need to be converted into channels of pixels at a certain bit-depth to be worked with?

to make it simple... it takes all 12/14 bit values recorded for same "color" (R, G1, B, G2) sensels and dump them all into a separate 16bit tiff file... so you will end up w/ values for all R sensels in r-tiff, values for all G1 sensels in g1-tiff, etc... no demosaicing of any kind... 4 files, each 4 times less dimension wise than original raw
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Mark D Segal

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Re: Monochrome r/g/b images from raw?
« Reply #14 on: May 03, 2012, 06:27:39 PM »

to make it simple... it takes all 12/14 bit values recorded for same "color" (R, G1, B, G2) sensels and dump them all into a separate 16bit tiff file... so you will end up w/ values for all R sensels in r-tiff, values for all G1 sensels in g1-tiff, etc... no demosaicing of any kind... 4 files, each 4 times less dimension wise than original raw

OK, taking it further then, what in your view is the difference between these results and what you get from individual image channels in say Photoshop?
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Mark D Segal (formerly MarkDS)
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #15 on: May 03, 2012, 06:31:35 PM »

Going back to the OP in light of some of the responses here, it seems to me that the proposed options are rather arcane - in the sense that they require very above average computing skills to work with them. I'm wondering what the purpose of the request is and in that context whether there is a simpler, more conventional solution.

may be likes "it" raw... by the way for a B/W photo sometimes I like to use undemosaicked image, w/ no WB or camera profiles applied, raw data output ( -NoCFA YES flag in RPP - it will output a greyscale 16 or 32 bit image) - just a curve and exposure adjustment - move it to photoshop and finish there... even from a camera w/ CFA not removed
« Last Edit: May 03, 2012, 06:33:10 PM by deejjjaaaa »
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dreed

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Re: Monochrome r/g/b images from raw?
« Reply #16 on: May 03, 2012, 06:44:13 PM »

..

http://www.libraw.org/data/LibRaw-0.14.6-Win32.zip

do not ask me how to extract from archive though !

Thanks! 4channels.exe does exactly what I wanted.
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #17 on: May 03, 2012, 06:53:18 PM »

OK, taking it further then, what in your view is the difference between these results and what you get from individual image channels in say Photoshop?

1) no demosaicking happened

2) pixels = same type sensels (only R sensels or only B sensels or only G1 sensels or only G2 sensels - other channels are totally removed)
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dreed

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Re: Monochrome r/g/b images from raw?
« Reply #18 on: May 03, 2012, 07:10:34 PM »

I should expand on this a little...

My interest here was to see how B&W images that result from using just a single channel of pixels compares with downsizing a colour image converted into B&W.

Also in this test is to see if there is less chromatic aberration due to different wavelengths focusing at different locations on the sensor.

Finally, it gives me a good sense for how much sharpness I should be applying in LR. Before being able to look at the per-channel images, I was just guessing about how much correction to apply (if any.)

The catch is that the output from 4channels.exe does need work (brightening, etc) before it is really usable.

As an example of the difference, I've included 3 attachments. One is just the red channel from the file, one is colour (no adjustments) from LR, and one is after colour to B&W (no other adjustments) in LR. Of course the catch here is that the red channel is 1/4 of the size of the other two.
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deejjjaaaa

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Re: Monochrome r/g/b images from raw?
« Reply #19 on: May 03, 2012, 07:31:42 PM »

My interest here was to see

if you just want to see then rawdigger is the software to use...

if still paranoid

Quote
Error message: "RawDigger BETA cannot continue without Internet access"

RawDigger Beta relies on Internet access for timely updates and will not work without it. We apologize for this inconvenience but we need to ensure the User has the last available version of the program. This allows for more efficient technical support.

RawDigger reads the settings for Internet access from the system setings (Control Panel -> Internet Options -> Connections -> LAN Settings).

To disable the update check on the next program run you can double-click on noCheckUpdates.reg located in C:\Program Files\LibRaw\RawDigger. Windows Registry Editor will be started and update check will be disabled for the consequative RawDigger run. The setting has one-time effect and is reset upon the program start. To restore it for the next program start you need to repeat the above procedure.

you can script that into some batch file like

regedit /s "C:\Program Files (x86)\LibRaw\RawDigger\noCheckUpdates.reg"
"C:\Program Files (x86)\LibRaw\RawDigger\rawdigger.exe"

OR

REG ADD "HKEY_CURRENT_USER\Software\LibRaw LLC\RawDigger\Tweaks" /v "noCheckUpdates" /t REG_DWORD /d 1 /f
"C:\Program Files (x86)\LibRaw\RawDigger\rawdigger.exe"

« Last Edit: May 03, 2012, 07:56:05 PM by deejjjaaaa »
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