Method and apparatus for paint inspection

摘要

Video monitors sequentially displaying coarse bar patterns of various spatial frequencies are spaced two feet or more from a painted surface to be inspected. Video cameras, also spaced far from the surface, view the images reflected from the paint and a computer system analyzes the images by determining the modulation transfer function (MTF) of each reflecting surface. Surface curvature is compensated for by selecting the spatial frequencies in the sequence of patterns in accordance with the effect of the curvature on a reference pattern. The area under the MTF curve correlates to the distinctness of image of the surface and the area under the low spatial frequency portion of the curve correlates to orange peel.