摘要 |
The present invention provides a method for dynamically refine the threshold values of R (Red), G (Green), B (Blue) colors for determining a borderline pixel in response to the values of a background image, thereby to precisely determine the borderlines of the Area of Interest (AOI). The method of the invention first searches the borderline pixels of a scanned image according to the standard differences of the R, G, B values of the pixels. Then, approximate the R, G, B threshold values of the borderline pixels by repeatedly averaging the current R, G, B values of the borderline pixels and the previous R, G, B threshold values until the difference is less than a predetermined value. The approximated R, G, B threshold values are set for the new R, G, B threshold values for determining the attribute of a pixel for subsequent prescanned images. Accordingly, the AOI can be automatically selected by reading the image circumscribed by the borderline pixels.
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