Promising experiments with a second histogram equalization stage after differentiation and pseudo color mapping.
I recommend to turn off all automatic features (autofocus, exposure/shutter, gain, white balance) on your camera to avoid flickering images and "pumping". Linux users who use a webcam can use guvcview in control panel mode to control the camera without causing a busy v4l device:

guvcview -z -d /dev/video1 This controls my second (external) camera.