Post-processing circuit according to the frequency components of the image signal

A post-processing circuit is provided to perform various post-process modes through one post-processing circuit by differently post-processing an image signal according to the post-process modes. A low frequency extracting unit(110) outputs a low frequency image component of an image signal as a low frequency signal. A high frequency extracting unit(120) outputs a high frequency signal by multiplying a high frequency image component by the first gain. A middle frequency extracting unit(130) outputs a high frequency signal by multiplying a middle frequency image component by the second gain. An adding unit(140) outputs a post-processed output signal of the image signal by adding the low frequency signal, the high frequency signal, and the middle frequency signal. The first gain and the second gain are differently set according to pixels in a space area displayed by the image signal. A low frequency image component, a high frequency image component, and a middle frequency image component are differently post-processed according to purpose of post-process.