LUMINANCE GRADIENT DIRECTION DETECTOR AND LUMINANCE GRADIENT DIRECTION DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a luminance gradient direction detector which fast detects a luminance gradient direction without using a triangular function with much computational complexity and a luminance gradient direction detection method.;SOLUTION: Eight pixels surrounding a pixel of interest are numbered in order in a clock-wise direction (B1) and eight luminance differential values in a point-symmetric direction around the pixel of interest are determined from luminance values of the eight pixels (B2). A maximum luminance differential value is determined from among the eight luminance differential values (B3) and temporary numbers are assigned to eight pixels in order in the clock-wise direction in such a manner that a pixel in a direction having the maximum luminance differential value becomes a central number (B4). Regarding the central number and temporary numbers of pixels at both sides of the central number, a weighted average value of the temporary number is determined with the maximum luminance differential value and luminance differential values of pixels at both the sides as weights (B5). Then, the central number is subtracted from the weighted average value of the temporary number and the number of the pixel in the direction having the maximum luminance differential value is added, thereby detecting a luminance gradient direction in the pixel of interest (B6).;COPYRIGHT: (C)2012,JPO&INPIT