Patent ID: 7986855

Claim:
A block noise detector that receives an input video signal including pixel values and a horizontal synchronizing signal, and detects block boundaries due to block noise with an assumed block width, comprising: a spatial difference comparator for calculating spatial differences by calculating differences between the pixel values of mutually adjacent pixels in the input video signal, detecting edges by comparing the calculated spatial differences, and outputting a decision signal indicating, for each calculated spatial difference, whether an edge is detected at a corresponding position; a phased accumulator including a plurality of counters for cyclically receiving the decision signal, counting edges detected at different phases in the receiving cycle, and outputting count values at a timing synchronized with the horizontal synchronizing signal; and a maximum sum and phase detector for outputting a maximum value signal having a maximum value among the count values output by the counters at said timing, and a maximum phase signal indicating a phase at which the maximum value occurs; wherein the block noise detector outputs a detected block phase signal indicating a detected block phase at which block boundaries occur, based on the maximum phase signal.