发明名称 |
Image processing apparatus |
摘要 |
An image processing apparatus includes a detecting section for detecting a density value as a threshold value for suppressing an effect from a background from image data composed of plural picture element data obtained by digitizing each picture element of the image and a density converting section for outputting the image data after converting density values of the picture element data whose density values are below the threshold value into a predetermined value indicating white when the density value of the picture element data is below the threshold value. The detecting section computes a degree of separation indicating a ratio of a between-class dispersion to a within-class dispersion of two classes divided by the threshold value by sequentially varying the density value. Then, the density value corresponding to a gravitational center of a differential histogram showing the respective differences in degree of separation from a density Tm which maximizes the degree of separation to a highest density Te. The apparatus enables an effective threshold value to be set even with respect to the image data wherein a difference in density level between the background and the image is not significant, thereby enabling the removal of the background from such image data.
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申请公布号 |
US5699454(A) |
申请公布日期 |
1997.12.16 |
申请号 |
US19950433227 |
申请日期 |
1995.05.02 |
申请人 |
SHARP KABUSHIKI KAISHA |
发明人 |
NAKAI, YOSHIYUKI;YAMAMOTO, YOUICHI;TANIGUCHI, KEIJI |
分类号 |
H04N1/407;G06K9/38;G06T5/00;H04N1/403;(IPC1-7):G06K9/38 |
主分类号 |
H04N1/407 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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