[camera_calibration] Doesn't work well with mono16 images

[mintar]

When running cameracalibrator.py on a mono16 image stream, the image appears all white. This is because cameracalibrator.py simply clips all gray values to the lowest 256 values:

calibrator.py:247

IMO, it should multiply each gray value by 1/256 instead.

I have verified this on my own image data: When I multiply the input image by 1/256 before feeding it into cameracalibrator.py, it works.

[mintar]

There's an open pull request that solves this issue: #334

[JWhitleyWork]

Closed by #334.