Uniform filter to compensate for global inaccuracies using photometric stereo

Abstract

In an example embodiment, a uniform filtering technique is applied using photometric stereo to reduce or eliminate global defects in a scanned component. An image is taken of a component using a photometric stereo technique. A uniform filter then, for every point in the component, takes an average of heights of the points near it. This essentially 'blurs' the image. The blurring may be repeated multiple times. The blurred image may then be subtracted from the original image, essentially flattening out the image in a manner that reduces or eliminated global inaccuracies. The post-filtered image can then be used for defect detection, with that defect detection being more accurate because of the reduction of the global inaccuracies.