Specified color area demarcation circuit, detection circuit, and image processing apparatus using same

Abstract

A specified color area demarcation circuit 6 has a luminance information (histogram) acquisition unit 3 for multiple pixels and a luminance information (histogram) analysis unit 5 for the multiple pixels. The luminance information (histogram) acquisition unit 3 for the multiple pixels acquires luminance information of the multiple pixels in an input image. In order to acquire the luminance information of the multiple pixels, the luminance information (histogram) acquisition unit 3 creates, for example, a histogram of the luminance indicating frequencies. As an example of the histogram, 0 to 255 gray levels in an image are divided into thirty-two (0-7, 8-15, . . . 240-247, 247-255) ranges, and the number of pixels present in each of the divided gray levels (luminance Y) is counted. In order to extract the feature value of the luminance information of the multiple pixels in the input image, the luminance information analysis unit 5 analyzes, for example, the histogram of the luminance values of the multiple pixels to extract the feature value representing a feature of the histogram. On the basis of the feature value, the luminance information analysis unit 5 obtains the coefficient for demarcating the specified color area. Thereby, it is possible to display an image of the specified color area with high precision.

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