| 摘要 |
<p>A sharpness processing apparatus for enhancing or suppressing tone variations in an original image. A lookup table (12) for converting RGB signals into HSL values which are the three attributes of perceived colors is used to obtain HLS values of pixels in the original image stored in a frame memory (2). The HSL values (14) of the pixels are successively compared (16) with HSL values (11) indicating an effective range of sharpness processing determined with reference to a designated reference color (6), to determine pixels to be subjected to the processing. The processing is effected by applying a parameter (13) to the RGB signals of the pixels subjected to the processing. In this way, the apparatus facilitates designation of a region of sharpness processing. Besides, the value of the parameter (13) is variable with differences between the HSL values of the pixels corresponding to the reference color (6) and the HSL values of the pixels (14) determined to be subjected to the processing, whereby the sharpness processing is effected without impairing smoothness of the original image. <IMAGE></p> |
