Patent ID: 6898318
Filing Date: 2005-05-24
Classification: G06K,G06T

Abstract:
1. An image processing method of reading image data of pixels in an image to be processed from, from a memory for storing an image data value of each pixel in said image, and obtaining an average value of image data of pixels in each of a plurality of rectangular regions defined as a plurality of rows and a plurality of columns in said image, in turn in the row direction, said method comprising the steps of: obtaining an average value of image data values of pixels in a first rectangular region by using an average value of image data values of pixels in a second rectangular region which was processed previously to calculate an average value of image data values of pixels in said first rectangular region, having a partial region in common with said rectangular region, and using a difference between image data values of pixels included in said first rectangular region and excluded from said second rectangular region and image data values of pixels included in said second rectangular region and excluded from said first rectangular region; wherein said difference is calculated by using a first image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said first rectangular region and excluded from said second rectangular region, image data values of which have been read out previously to calculate said average value of image data values of pixels in said first rectangular region, a second image data value of the bottom pixel in said area of pixels included in said first rectangular region and excluded from said second rectangular region, a third image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said second rectangular region and excluded from first second rectangular region, a fourth image data value of the bottom pixel in said area of pixels included in said second rectangular region and excluded from said first rectangular region.