Ringing detector and filter

摘要

The ringing detector of the invention receives data representing pixel values of a plurality of pixels including: a remarked pixel; a number L (where L is a natural number) of neighboring pixels which are located in the vicinity of the remarked pixel; and a number M (where M is a natural number) of surrounding pixels which are more distant from the remarked pixel than the neighboring pixels are, thereby generating a ringing constant t indicating whether or not a ringing exists in the vicinity of the remarked pixel. The ringing detector includes: a pixel value variation detector for calculating a value x corresponding to a variation in the pixel values of the neighboring pixels; a distance detector for calculating a value y corresponding to a distance between the pixel values of the surrounding pixels and a barycenter of the pixel values of the remarked pixel and the neighboring pixels; and a ringing constant calculator for calculating the ringing constant t based on the values x and y.