Color artifact reduction Apparatus and Method using adaptive-mean filter

摘要

A color noise removal apparatus using an adaptive average value filter and a method therefor are provided to enhance compression efficiency and acquire an image of high image quality by removing a color noise due to the estimation failure of directionality in color interpolation or information insufficiency in a preprocessing stage of a compression codec. A color interpolation unit(21) performs color interpolation and outputs a color-interpolated image. The first adaptive average value filter(22) searches similar pixels in a local region of the color-interpolated image, obtains the number of the similar pixels, a maximum value, and a minimum value, and calculates an average value of the similar pixels except for the maximum value and the minimum value. The second adaptive average value filter(23) calculates an average value of the other pixels except for the maximum value and the minimum value among all pixels in the local region of the color-interpolated image. An average value selecting unit(24) compares the number of the similar pixels of the first adaptive average value filter with a reference number. If the number of the similar pixels is bigger than the reference number, the average value selecting unit selects the output of the first adaptive average value filter. If the number of the similar pixels is the same or smaller as or than the reference number, the average value selecting unit selects the output of the second adaptive average value filter. A color noise removal execution judging unit(25) compares an original value in the local region with the average value, and judges whether a current region is a low frequency region or a high frequency region. When the current region is the high frequency region, the color noise removal execution judging unit outputs the image selected in the average value selecting unit and removes a color noise. When the current region is the low frequency region, the color noise removal execution judging unit exactly outputs the color-interpolated image and does not perform noise removal.