Patent ID: 8390890

Claim:
A halftone image generation method used in a system for generating a halftone image, wherein the system at least comprises an image input module and a halftoning processing module, comprising: receiving an original image by the image input module; and performing a dot diffusion process to the original image to generate the halftone image by using a first class matrix with a first size and a corresponding first diffused weighting matrix with a first diffused area size, wherein the first class matrix indicates a processing order of the dot diffusion process and the first class matrix with the first size, the first diffused area size and the corresponding first diffused weighting matrix with the first diffused area size are optimized results determined in advance by the halftoning processing module performing a weighting calculation and a quality evaluation to at least one reference image according to class matrixes of different sizes and diffused areas of different sizes, wherein the step of that the halftoning processing module performs the weighting calculation and the quality evaluation to at least one reference image according to class matrixes of different sizes and diffused areas of different sizes further comprises: providing an initial class matrix and an initial diffused weighting matrix respectively selecting one of the diffused area sizes to test the initial class matrix; successively selecting a member from the selected diffused area size of the initial class matrix being tested and swapping each member in the class matrix with one of the other remaining members to generate a swapped class matrix; performing a diffused weighting adjustment for the initial diffused weighting matrix to generate an adjusted diffused weighting matrix under each swapping operation based on a specific rule; performing the dot diffusion process with each swapped class matrix and each adjusted diffused weighting matrix to generate corresponding second halftone images; calculating a second average PSNR for each of the second halftone images; and obtaining the first class matrix and the corresponding first diffused weighting matrix according to each of the second average PSNRs, wherein the specific rule comprises configuring higher values for pixels nearer to the center of the diffused weighting matrix within the diffused weighting matrix, configuring a same value for pixels with the same Euclidean distance to the center of the diffused weighting matrix within the diffused weighting matrix and configuring a fixed value 1 for pixels which are vertical and horizontal four pixels nearest to the center of the diffused weighting matrix.