Method of median filtering

摘要

A median filtering method makes a plurality of pixel data into a block of fixed unit area which includes a central pixel and a plurality of ambient pixels adjacent to the central pixel. Pixel data within the unit area is divided into sub unit areas which are smaller than the unit area. The data value of the divided pixel data is arranged in a fixed order for each of the sub unit areas. An intermediate value is determined from the arranged pixel data in each of the sub unit areas. An average value of the intermediate values which are extracted from each of the sub unit areas, and the central pixel data is determined corresponding to the central pixel of the unit area with the average value.

主权项

1. A median filtering device operable to perform a median filtering method, the method comprising:
forming a unit area which includes a central pixel and a plurality of ambient pixels arranged to be adjacent to the central pixel, wherein the unit area is a block such as m*m (where m is a natural odd number greater than 1); dividing the unit area into a plurality of sub-unit areas which are smaller than the unit area, each sub-unit area corresponding to a pixel and having a pixel data value; selecting a first pixel group including the central pixel and a part of the ambient pixels, wherein the first pixel group is the pixels selected of a cross direction including a horizontal direction and a vertical direction on the central pixel; selecting a second pixel group including the central pixel and a remaining part of the ambient pixels that are not selected in the first pixel group, wherein the second pixel group is the pixels selected of diagonal directions including a left diagonal direction and a right diagonal direction on the central pixel; extracting a first intermediate value from pixel data values of the first pixel group, wherein the first intermediate value is a middle-sized value of all the pixels data values of the first pixel group; extracting a second intermediate value from the pixel data values of the second pixel group, wherein the second intermediate value is a middle-sized value of all the pixels data values of the second pixel group; calculating an average value based on the first intermediate value and the second intermediate value; determining a central pixel data value by comparing the first and the second intermediate values with a current central pixel data value, and if a coincidence between at least one of the first intermediate value and the second intermediate value and the current central pixel data value exists, maintain the current central pixel data value, and if no coincidence exists, replacing the current central pixel data value with the average value.