| 摘要 |
PURPOSE:To detect an edge position with a high resolution and a low error by calculating a difference in luminance between pixels, i.e., a differential value, by converting the value into each of small, medium, large or other index values and by calculating a synthesized central value of each edge existence width and the central position in the direction X in a prescribed area. CONSTITUTION:A differential value Di of each pixel of prescribed areas Xebl to Xeel is converted into a value showing the degree of belonging to each of small, medium, large and other indexes representing luminance ambiguously and further converted into an edge existence width in conformity with an edge existence width conversion function made to correspond to each index, and a synthesized central value Wwi of the width is calculated. This value Wwi can be determined for each one pixel Xi. On the assumption that an edge exists within the range Xi+Wwi from each position of Xi to Wwi, in other words, the position of each pixel Xi of the areas Xebl to Xeel is weighted with a reciprocal of the value Wwi and the central position Ejcpl in the direction X of the areas Xebl to Xeel is calculated. This is concluded to be the center of the edge (line) and thus an edge center is obtained. Therefore, edge center information (Ejcpl) of a higher resolution than a pixel pitch is obtained. |
