| 摘要 |
PURPOSE:To make it possible to extract a target even when the altitude of a radial scanning apparatus is high, by removing unnecessary information such as background noise from the signal from the radial scanning apparatus. CONSTITUTION:The light scanned by a radial scanning optical system 2 is converted to an electric signal by a light receiving element 3 and quantized by a first A/D converter 7 through a first sampling device 5 while the background noise of the scanning optical system 2 present at a high altitude place is removed by a filter 36 and the output 37 of said filter 36 is quantized by a second sampling device 48. These outputs 41, 8 are respectively inputted to second and first effective value detectors 42, 44 to respectively measure effective values 43, 44 which are, in turn, selected by a detector selection circuit 46 to output a selection signal 47. A level detector 9 binarizes output 8 to detect the center-of-gravity position 50 of a target from coordinates exceeding a threshold value. An edge detector 48 detects a point (edge position 49) where the timewise change ratio of the output 41 becomes max. A selector 51 detects the position 50 when the value of the signal 47 is 0 and detects the position 49 as the presence position 10 of the target when said value is 1. |
