| 摘要 |
The printer of the invention performs an area classification process to classify each pixel included in an input image read by a scanner as a pixel in an edge component area or a pixel in a halftone dot area, and performs a correction process with a spatial filter suitable for each area. The area classification process calculates a difference value between luminance values of two arbitrary pixels selected among peripheral pixels in a specific pixel range around each target pixel according to each of multiple differential patterns t, compares the calculated difference value with threshold values provided for each differential pattern t to compute multiple difference detection values ht(x) corresponding to the multiple differential patterns t, and gives weights to the computed difference detection values ht(x) to compute a comprehensive difference detection value H(x). The area classification process identifies whether the target pixel is a pixel in the edge component area or a pixel in the halftone dot area, based on the computed comprehensive difference detection value H(x). This arrangement enables high-speed identification of the attribute of each pixel included in an image by such simple operation, while enabling identification of pixel attribute with high accuracy.
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