Calibration Plate Image Requirements

The physical dimensions (grid pitch) of the calibration plate must be chosen such that in images acquired through your camera and optics, checkers are no smaller than 15 x 15 pixels. Note that 15x15 pixels is the extreme low end of the operating range and for most applications the checker size should be larger so you are not operating on the range limit.

If your calibration plate does not include a fiducial mark, images must contain at least a grid of 3x3 checker vertices. See the figure below.

Example image containing a 3x3 grid of checker vertices

If your calibration plate does have a fiducial mark, the image must contain at least two rows and columns surrounding the fiducial mark. The dotted line box in the figure below outlines the minimum image size.

Example of fiducial image requirement

Checkerboard calibration specifications