| 摘要 |
PURPOSE:To attain binary coding processing with high accuracy at all times by eliminating a deviation of illuminance on the surface of a work even if it exists, by means of a simple electric processing. CONSTITUTION:If the exists a deviation such as brighter center part on the illuminance of the surface of a semiconductor pellet 1, a video signal (a) becomes a barrel-shaped waveform, and a voltage level converting signal (c) multiplied by 1/2 at a level converting circuit 7 is a barrel-shaped waveform as shown in broken lines in figure. Further, a voltage level of a DC reference level signal (d) added with the signal (c) is set so that the sum signal (e) becomes a waveform in broken lines in figure by expecting the difference between the dark/ bright part of white part m1 and black part m2 of a picture M. As a result, a voltage level of the sum signal (e) to the white part m1 is always lower than the voltage level of the video signal (a) to the white part m1, inversely the voltage level of the sum signal (e) to the black part m2 is always higher than that of the video signal (a), and a binary-coding signal (f) obtained by the comparison of the voltage level of both signals (a), (e) expresses accurately the surface state of the semiconductor pellet 1. |
