US Patent 7106386 Device and method for improving picture quality

A picture quality improvement device has two-dimensional low-pass filter that takes as input a luminance signal YIN that is obtained from a video signal and that extracts low-pass components for a vertical direction and a horizontal direction of the input luminance signal YIN. The picture quality improvement device adds an edge signal, which is obtained by subtracting from luminance signal YIN the low-pass extraction signal (LPF) that has been extracted by two-dimensional low-pass filter, to luminance signal YIN. Two-dimensional low-pass filter is constituted such that the extraction gain of the vertical direction low-pass component and the extraction gain of the horizontal direction low-pass component are independently adjusted.