Patent ID: 6055336
Filing Date: 2000-04-25
Classification: G06K,H04N

Abstract:
A method of converting multi-value image data having a first resolution into binary image data having a second resolution, the second resolution being greater than the first resolution, the method comprising the steps of:obtaining the multi-value image data having the first resolution, the multi-value image data comprising plural pixels each having a pixel density value; andbinarizing the multi-value image data having the first resolution to produce the binary image data having the second resolution, the binarizing step binarizing a target pixel in the multi-value image data based on pixels adjacent the target pixel,wherein the binarizing step further comprises the steps of subdividing the target pixel into plural sub-pixels, each sub-pixel corresponding to a binary pixel in the binary image data, and binarizing each sub-pixel based on a sum of weighted pixel density values for the target pixel and pixels adjacent the target pixel, andwherein for each sub-pixel, weights used to calculate the weighted pixel density values include at least a first non-zero weight and a second non-zero weight, the first non-zero weight for a first pixel that is adjacent the target pixel and adjacent the sub-pixel, and the second non-zero weight for a second pixel that is adjacent the target pixel but not adjacent the sub-pixel.