Patent ID: 7330599

Claim:
A contour compensation circuit that generates a contour-compensated signal, by which a signal level of a contour of an object is emphasized, from an image signal obtained by an image pickup of the object, wherein the generation of the contour-compensated signal is performed regarding one channel of channels that consists the image signal as a standard channel, and wherein the generation of the contour-compensated signal is performed in order to prevent an occurrence of a colored edge on the contour of the object, that are caused when the contour of the object is emphasized, and the contour compensation circuit comprising: a reverse gamma controller, which performs a reverse gamma control on the standard channel, and obtains a liner standard channel; a contour compensation signal generator, which generates a contour compensation signal from the liner standard channel; a control signal generator, which computes a comparative value from the liner standard channel and the contour compensation signal, and generates an evaluation value from a comparison between the comparative value and a threshold value, and the control signal generator generates a plurality of delayed evaluation values by the delay of the evaluation value, and select a minimum value from among the evaluation value and the delayed evaluation values, and output a selected minimum value as a control signal; a calculator, which computes the contour-compensated signal based on the contour compensation signal, and the control signal, and the liner standard channel; a contour compensation signal retarder, which receives the contour compensation signal from the contour compensation signal generator, and supplies the contour compensation signal to the calculator with delay; and a reverse gamma signal retarder, which receives the liner standard channel from the reverse gamma controller, and supplies the liner standard channel to the calculator with delay.