| 摘要 |
PURPOSE:To measure deviation in an optical axis through a video camera by fitting a light shield plate which has a phototransistor TR fitted at the center part to the center of a diffusing plate, and providing negative feedback to the output of the phototransistor so that the illuminance in the center of the light shield plate by the light emission of a light projector is constant. CONSTITUTION:A control part 12 outputs a measurement start signal S2 to a measuring part A, and the projection of a light emitting diode 1 on the diffusing plate 4 is converted by the video camera 5 into a projection signal V0, which is outputted to a binary-coding amplifier 8. When this value is larger than a threshold VTH, the signal is converted into a binary-coded video signal V0', which is outputted to an arithmetic part 9. Area, circumferential length, etc., are measured by the feature extracting method of video processing by using the white level of the V0' and a sampling clock phi from a synchronizing signal generating circuit 7 to output measurement signal data to a decision part 10. The decision part 10 compares the measurement data with a set value corresponding to the limit value of the standard of optical axis deviation to decide on a conforming article when the data is smaller than the set value or a nonconforming article when not. Consequently, the quality is stabilized. |
