This release adds support for the --invert option, which will output an image with a white background:
./brdiff --invert image_735nm.jpg image_660nm.jpg image_br_whitebg.jpgThe output image's pixels will still appear blue for positive difference values and red for negative difference values, but because of the way RGB channels work, it actually subtracts the "difference" value from the other respective two channels (red and green, in the case of a blue-appearing pixel; blue and green, in the case of a red-appearing pixel).