Please complete this task as part of your GSoC 2019 application when applying for matching tasks/ideas.
This challenge is mandatory if you apply for T763 or T1121.

1. Write a C/CPP program for loading a RAW12 image (portrait-gainx2-offset2047-20ms-02.raw12) into the memory - separate the 4 channels (in memory - 8 bits). Output the intensity values of the first 5x5 pixels (square tile) R, G, G, B channels.
2. Save the channels (separately) as valid image files (8 bits per pixel) named appropriately without use of any external libraries (e.g. openJPG/lodePNG). (Hint: PPM file format).
3. Debayer the CFA (color filter array) data (in memory using nearest neighbour / bilinear) - output the image as a valid image file (8-bit, without use of any external library).

Additional task (for T763):

4. Save the debayered RGB image as a BMP file (without use of any external libraries) - expected that you create the BMP file from scratch. As an alternative, you can save the image as a single frame in an AVI file without use of external libraries (bonus points).

Additional points (if you do one / some / all of the following):

1. Use cmake for building the C/CPP program
2. Abide by the C/CPP coding guidelines (https://gist.github.com/lefticus/10191322) and project structuring (create appropriate directories, header files, c/cpp files to modularize the code in meaningful ways). See collected information below.
3. If you can load part of your program as a dynamic library (.so file)
4. If you use a nonlinear curve for the 12 to 8 bit conversion, without ignoring the bottom 4 bits (lots of different solutions possible) and explain your choice (why did you choose that curve)

Collected information:

• RAW12: https://wiki.apertus.org/index.php/RAW12
• Bayer Pattern: https://en.wikipedia.org/wiki/Bayer_filter
• 12bit conversion: https://stackoverflow.com/questions/33768206/convert-2-bytes-into-12-bit-number
• 12bit conversion (SIMD not required): https://stackoverflow.com/questions/15443868/fastest-way-to-convert-12bit-image-to-16bit-image
• Processing RAW images in MATLAB (useful as overview; we are not asking for color-correct output)
• Debayering: https://en.wikipedia.org/wiki/Demosaicing
• PPM file format: https://en.wikipedia.org/wiki/Netpbm_format
• CPP modularity StackOverflow: https://stackoverflow.com/questions/3548357/how-do-you-carry-out-modularized-development-in-c-c
• BMP/AVI file format: https://www.springer.com/cda/content/document/cda_downloaddocument/9781848000223-c2.pdf?SGWID=0-0-45-489703-p173751347
• http://files.apertus.org/AXIOM-Beta/optimal_curve.html

Note: Using or improving upon existing code is permitted but, in the event that code authored by someone else is used, the code's original author must be credited.

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