| 摘要 |
PROBLEM TO BE SOLVED: To extract embedded watermark information from a line interval of a character string in a document image with higher precision. SOLUTION: An image processing apparatus includes an image reduction means of generating reduced image data in a first direction from the input document image; and an extraction means of scanning the generated reduced image data in a second direction having a predetermined relationship with the first direction to generate a histogram of respective heights of an area comprising significant pixels, determining a range of the heights of an area regarded as an effective area in the reduced image data based upon the histogram, regarding at least an area comprising significant pixels having heights not within the range as a noise component and setting the area as insignificant pixels, scanning the reduced image having the noise component set as the insignificant pixels in the second direction to detect the length of the area of the insignificant pixels successive in the second direction as a line interval, and extracting the watermark information embedded in the document image based upon the line interval of the character string detected by the detecting means. COPYRIGHT: (C)2009,JPO&INPIT
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