Hello, my first post. In fact, if this wouldn’t work in Gimp, not to rule that out, I’ll need entry level hand-holding to point me to the right (open source preferably) tool, like RawTherapy? My preprocessing workflow going into photogrammetry has been limited to Lightroom, which assumes RAW input, but then RGB output is always demosaic’d or deBayered. My source data being 42 MP under controlled lighting and such provides RealityCapture (RC)a nice dataset for producing a high quality model with plenty of 8K textures that look king, but this first step, scene reconstruction, the resolution of the geometry is compromised by the demosaicing of the source imagery, so I’m curious to experiment with a couple of ideas. The first idea is simply to present RC the non-demosaic’d imagery and see if it can handle feature detection. Whether this input is in grayscale, with each pixel location or “sensel” simply feeding luminance values, or including the actual R, G, B color (as described in this post), I’m not sure what’s implied with the two methods, but I’d expect RC to value “more” data, just uncertain if in the Bayer pattern form the color is in play in the way RC’s algorithms are set up to analyze pixels.
The second idea is to apply sharpening to this non-demosaic’d image to yet improve resolution of the geometry. In this paper by Dr. Zhang, an inventor of a pan-sharpening tool used in processing global imagery, I’m clearly not reinventing the wheel, simply borrowing from a proven and effective technique used in a system that somewhat relates to photogrammetry, insofar tiling and such involves feature detection in overlapping regions of related photography. The difference here is, his methods involve multi-spectral photography and panchromatic photography, the latter of which doesn’t need demosaicing and is used with pan-sharpening in combo with, well suffice it to say, I’m getting warmer to what I’m after, but am reaching the limit of my knowledge.
The link I provided in connection with that first idea should suffice to produce a 16-bit TIF containing non-demosaic’d imagery, but it’s not clear how to achieve this in Gimp. Any thoughts on that? Or any ideas on if RawTherapee is the tool, thanks for advising. Same goes for the concept of pan-sharpening, any thoughts on how best to approach that idea are most appreciated.