| 摘要 |
PURPOSE:To stably generate a proper edge image without being affected by space quantization. CONSTITUTION:A gradation image signal is applied from an image pickup device 2 to an edge image generator 1, and the first-order differentiating value and the second-order differentiating value of the image data of a gradation image are respectively calculated by a first-order differentiating calculation part 4 and a second-order differentiating calculation part 5. A binarizing processing part 7 binarizes the first-order differentiating value at a prescribed threshold value. A zero cross detection part 9 detects the zero cross point of the second-order differentiating value by a mask processing. An AND circuit 8 of the edge extraction part 6 inputs binary data from the binarizing processing part 7 and detected data from the zero cross detection part 9 and when the both respective input data are '1', as an AND output, edge image data are turned to '1'. |
