Method for recognizing and evaluating faults in semi-reflecting superficial film

摘要

The sheet of glass to be examined (1) is placed horizontally in a support frame (2) and is illuminated uniformly with white light from a source (4). The light falling on the glass plate is reflected on to a screen (6). The image appearing on this screen is captured by one or several colour video cameras (12-15). For each primary colour, and for each point on the image the luminance is determined, and the relative colour reaction for each colour is calculated by dividing the luminance value for one colour by the sum of the luminance values for that point. These relative colour fractions are then compared with predetermined reference values.