The square size sqw of the checkerboard pattern, that limits the accuracy of segmentation, is identified as the major source of error. Under the assumption of a target that entirely fills the viewable area and does not exhibit other kinds of distortion, the expected error is dependent on the square size sqw. As an upper bound, the error may be assumed to be double th esquaresize then. The minimumus able square size sqw is dependent on the image resolution. If we assume that pills may be correctly segmented under the previous conditions, the maximum error emax can be estimated as follows: