Patent ID: 7006704

Claim:
An apparatus for improving quality of a picture, comprising: a two-dimensional low-pass filter for being supplied with a luminance signal obtained from a video signal and extracting, from the supplied luminance signal, low-frequency components in vertical and horizontal directions of a picture displayed based on the video signal; a subtractor for subtracting the low-frequency components extracted by said two-dimensional low-pass filter from said luminance signal thereby to generate an edge signal; and an adder for adding said edge signal generated by said subtractor to said luminance signal; said two-dimensional low-pass filter comprising a vertical low-pass filter for extracting the low-frequency component in the vertical direction and a horizontal low-pass filter for extracting the low-frequency component in the horizontal direction; said vertical low-pass filter having a first FIR (finite impulse response) filter and a first IIR (infinite impulse response) filter which are connected in cascade; said horizontal low-pass filter having a second FIR filter and a second IIR filter which are connected in cascade.