Patent ID: 8224060

Claim:
An image processing method that differentiates image data using an image processing system that includes a processing unit and a storage unit, comprising: an image data acquisition step of acquiring image data, which include a density of each pixel acquired by an image pickup apparatus, using the processing unit; a reference pixel acquisition step of sequentially picking up pixels one by one at a predetermined pitch from among the pixels that constitute the image data and setting the picked up pixels as reference pixels; a close region setting step of setting a predetermined region around each of the reference pixels as a close region; a first similar density acquisition step of picking up a predetermined number of pixels having a small difference in density with respect to the density of a corresponding one of the reference pixels in increasing order of a difference in density from among the pixels included in each close region, using the processing unit; a first similar density average calculation step of calculating an average value of densities of the pixels picked up in the first similar density acquisition step for each of the close regions, using the processing unit; a wide region setting step of setting a predetermined region larger than the close region around each of the reference pixels as a wide region; a second similar density acquisition step of picking up a predetermined number of pixels having a small difference in density with respect to a corresponding one of the average values calculated in the first similar density average calculation step in increasing order of a difference in density from among the pixels included in each of the wide regions, using the processing unit; a second similar density average calculation step of calculating an average value of densities of the pixels picked up in the second similar density acquisition step for each of the wide regions, using the processing unit; and a step of calculating a difference between the density of each of the reference pixels and a corresponding one of the average values calculated in the second similar density average calculation step, using the processing unit.