pgm2dng is a command line converter, that converts PGM files with raw CFA data into DNG format, that could be processed with raw processors (Adobe Camera Raw, Raw Therapee, Fast CinemaDNG Processor). Usually we get raw frame from machine vision or industrial camera as a bitmap of 8/10/12/14/16-bit values which we store as PGM (Portable Gray Map) image. Apart from bitmap we know bit depth and image resolution (width and height) for every frame. But this is not enough for good color reproduction. For raw processor to correctly work with resulting DNGs we also should provide some additional information:
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DCP (digital camera profile) file, that contains color transformation information (at least 3x3 color matrix and illuminant information). If you don't have this profile, you can do the following:
- Try to find sutable profile in the DCPProfiles folder of this repository.
- Try to find sutable profile in the internet.
- If you have DNG file from the camera of the same model, you can use dcptool to decompile it to xml file and compile that xml file into dcp.
- Create your own profile with DCamProf and color checker. You will need a shot of color checker in linear color space (some camera can shoot in log or other non linear color spaces, so you should switch it to linear mode). To create profile with DcamProf you will have to demosaic (debayer) raw image into RGB. For that purpose one can use fastDebayer freeware application from Fastvideo. For more details see Basic workflow for making a DNG profile using a color checker and DcamProf
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White point - RGB values of gray patch from color checker or gray card. These values provide correct white balance on processed image. One of the ways to obtain these values is to demosaic (debayer) raw image into RGB. For that purpose one can use fast_debayer freeware application from Fastvideo. Then open this image into graphics editor (Photoshop or GIMP) and get these values with color picker.
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CFA (bayer) pattern. This information is required for color processor to correctly convert raw to RGB image.
pgm2dng.exe command-line options: --in=< path/to/input/file > --out=< path/to/output/file > --dcp=< path/to/dcp/file > --wp=< R,G,B > --white=< white > --black=< black > --compress
Where:
--in=< path/to/input/file > - path to PGM file (mandatory). 8, 10, 12, 14, 16 bits per pixel PGMs are supported, but 10-bit PGMs are encoded as 16-bit DNGs.
--out=< path/to/output/file > - path to DNG file (mandatory)
--dcp=< path/to/dcp/file > - path to DCP (digital camera profile) file (mandatory)
--pattern=< pattern > - CFA pattern. Alowed values: RGGB, GBRG, GRBG, BGGR (mandatory)
--wp=< R,G,B > - comma separated white point values (mandatory)
--white=< white > - white level (optional, default is maximum for a given bit depth)
--black=< black > - black level (optional, default is 0)
--compress - compress image with lossless jpeg algorithm
To build pgm2dng from source you need Visual C++ 2017. For use with other compiler you should recompile XMP SDK. Currently it is built as a static lib with Visual C++ 2017, so if you need another compiler you should rebuild it with it and setup your build environment to point to correct lib files.
To build application with Visual C++ 2017:
- Open pgm2dng.sln file with Visual Studio 2017
- Set build configuration to Release
- Select Build\Build solution menu item or press Ctrl + Shift + B
- pgm2dng.exe will be placed into bin folder for release build and into src\x64 for debug build
To test the application, run test.cmd from bin folder. This script will process sample 8/10/12/14/16-bit PGM files from Samples folder with and without lossless jpeg compression.
Adobe DNG Software Development Kit (SDK) 1.4 - https://www.adobe.com/support/downloads/dng/dng_sdk.html
DCamProf software - https://www.ludd.ltu.se/~torger/dcamprof.html
RawTherapee - http://rawtherapee.com
Fast CinemaDNG Processor - https://www.fastcinemadng.com
Fastvideo Image & Video Processing SDK for CUDA - https://www.fastcompression.com/products/sdk.htm