- pix-clean-imageprocedure
- in - PPIX
- in - CONTRAST: int32 - 1 (lightest) to 10 (darkest)
- in - ROTATE: int32 - 0,1,2,3 (0,90,180,270 degrees cw)
- in - SCALE: int32 - 1 or 2 (for 2X upscaling)
- in - OPEN-SIZE: int32 - size for noise removal (0/1-none, 2,3 to use)
- returns: cleaned ppix or #f if error.