1) Demosaicing: for a list of demosaicing algorithms go to Amir Khashabi's webpage.
2) Denoising: for a very effective denoising method and code called BM3D (block matching and 3D filtering) check here.
3) Image processing libraries: CImg, OpenCV, ImageMagick, GraphicsMagick, Pink, GIL, Vips, TIPL, PIL.
4) Lens distortion and vignetting corrections: Fulla
5) Rendering raw image data from commercial cameras: DCRAW
6) Manipulate raw image data: UFRAW
Electromagnetic wave propagation:
See GitHub for some of my past codes: https://github.com/SalmanKarbasi