| 摘要 |
PURPOSE:To perform the picture image processing with no effect of the variance of light given from a light source by offsetting previously the black voltage of the variable density data corresponding to the surface of a matter to be checked. CONSTITUTION:The information equivalent to one screen which is image-picked up by an ITV camera 2 is offset by a black level voltage generating circuit 8 with the black level voltage and then stored by latch circuits 21-29 in the form of the density data. Then the edges are extracted out of a variable density picture image containing said density data by a differential method. In this case, the effect of variance of the luminous intensity of a light source 3 can be eliminated for picture processing since the voltage value of a black level is previously offset for the density data to be differentiated. |
