Patent ID: 6864923

Claim:
An edge correcting circuit of an image to be represented by a digitized image signal, comprising: a high-frequency signal extracting circuit for extracting a high-frequency signal of the image by calculation based on a signal of a pixel which is to be corrected (hereinafter called a target pixel), a signal of a pixel shifted from the target pixel by m (m being an integer not smaller than 2) pixels in the right or lower direction, and a signal of a pixel shifted from the target pixel by m pixels in the left or upper direction; an amplitude-restricting signal generator for determining an amplitude-restricting signal based on a minimum value or a maximum value of an absolute value of a difference between the signal of the target pixel and a signal of a pixel shifted from the target pixel by n (n being an integer not smaller than 1 and smaller than m) pixels in the right or lower direction, and an absolute value of a difference between the signal of the target pixel and a signal of a pixel shifted from the target pixel by n pixels in the left or upper direction; an amplitude restricting circuit for restricting the output of the high-frequency extracting circuit so that the absolute value of the output of the high-frequency extracting circuit is not more than the output of the amplitude-restricting signal generator; and an adder for adding the output of the amplitude restricting circuit or a signal obtained therefrom, as an edge correction signal, to the signal of the target pixel.