Sorry, can't help with CamScanner; this is the first I've heard of it.

In my case, most of the scans were similar. Once I figured out the necessary adjustments needed by using Gimp, I then used ImageMagick to process all of the scans (mostly adjusting gamma. I also wrote a script that let me use all available CPUs to process that many images at a time using ImageMagick, and another using Tesseract to OCR all those images using all CPUs. In short, I used Gimp to figure out what needed to be done to all of them, and ImageMagick to apply those adjustments to all of the scans.