Patent ID: 8139267
Filing Date: 2012-03-20
Classification: H04N

Abstract:
1. A method of operating a computation device to process an image using a threshold value matrix for quantization of an n-value signal in each pixel of the image into an m-value (n>m>1) using a dither process, the method comprising: (i) creating the threshold value matrix by: executing a first process of creating an initial dot pattern of a predetermined dot rate “a” and arranging a gradation value corresponding to the dot rate “a” at a pixel position of the threshold value matrix, the pixel position corresponding to the initial dot pattern, as a threshold value; executing a second process so as to generate a dot pattern of dot rate “b′” having a gradation value g+δg based on a reference pattern of dot rate “b” having a gradation value g, said second process comprising the steps of: (ii) processing the image using the created threshold value matrix.