GM requires suppliers to run the test (GMW17555) which replicates a standardized mechanical cleaning action and evaluates its effects on the viewing performance over time. For scratched lens, this method holistically provides measurement values that align subjective and objective evaluations. When lens is scratched, it disperses light and yields decreased contrast. Degradation of the contrast at the edges in the corresponding test images allows the subjective evaluation to be transformed into objective evaluation. The edge detection results are plotted on histograms. From these histograms, peak values are derived per image. The pass/fail criteria was then established by subjective evaluation image.