| 摘要 |
PURPOSE:To correct undulation of the video signal caused by unevenness of the illumination intensity of a detection illumination, by averaging the video signal of the background without patterns and by using the deviation value between this average value and video information of each picture element. CONSTITUTION:The detection region to be irradiated by an illumination light 1 is made smooth without patterns, and this region is detected by an image sensor 3. The signal of each picture element obtained from the sensor 3 is converted to a digital value 19 in a converter 5 and is stored in a storage circuit 9. After completion of this storing, digital values of all picture elements are read out from the circuit 9, and the average value is obtained by an averaging circuit 12. Average values obtained in this manner are read out successively, and deviation values for average values are obtained by a subtracting circuit 13 and are stored as correcting values in a storage circuit 14. Next, the sample surface is moved to perform detection by the sensor 3. Video information obtained successively and correcting values read out from the circuit 14 are added by an adding circuit 15. This addition signal is applied to a D/A converter 16 to obtain a sensitivity-corrected analogue video signal. |
