| 摘要 |
PURPOSE: To provide an edge image extracting device which finds edge pixels of a narrow width (e.g. 1-pixel width) without making the constitution complex and exerting any influence of a noise. CONSTITUTION: This device is provided with a 1st image memory 10 which stores data on a source image, a primary differentiator 50 which performs the primary differentiation of image data from the 1st image memory 10, a primary differentiator 52 which performs the primary differentiation of the output signal of the primary differentiator 50, a comparing decision unit 56 which judges an edge and outputs its image data C when the absolute value A of the output signal of the primary differentiator 50 is larger than a threshold value H and the output signal B of the primary differentiator 52 is at or nearby a zero-cross point, and a 2nd image memory 16 which stores the edge image data C. Further, a means required for edge processing is composed of the primary differentiators 50a and 52 of a simple constitution and the comparing decision unit 56, so that the device has both the advantages of primary differentiation processing (exclusion of the influence of a noise) and the advantages of secondary differentiation processing (width narrowing of edge pixel). |
