Patent ID: 8009327

Claim:
An image processing apparatus for quantizing input image data, the apparatus comprising: a bit connection component that connects a decimal portion of corrected image data of a preceding pixel output from a latch component, to input image data of a target pixel as lower bits of the image data of the target pixel, and outputs the bit-connected image data of the target pixel, wherein the bit-connected image data has an integer portion of the image data of the target pixel and the decimal portion of image data of the preceding pixel; a correction component that generates corrected image data of the target pixel by adding a correction value to the bit-connected image data of the target pixel; the latch component that latches a decimal portion of the corrected image data generated by the correction component of the target pixel by splitting-off, prior to performing quantization of the corrected image data, the decimal portion of the corrected image data from an integer portion of the corrected image data, output by the correction component, the split-off and latched decimal portion to be connected to image data of a next pixel by the bit connection component, wherein the latch does not latch the integer portion of the corrected image data of the target pixel; a quantization component that receives an integer portion of the corrected image data without receiving the decimal portion of the corrected image data of the target pixel, and quantizes the received integer portion of the corrected image data of the target pixel; an inverse quantizing component that inverse-quantizes the quantized integer portion of the corrected image data of the target pixel, and outputs an inverse-quantized data of the target pixel; a calculation component that outputs a quantization error of the target pixel based on a difference between the integer portion of the corrected image data of the target pixel and the inverse-quantized data of the target pixel; a buffer that stores the integer portion of the calculated quantization error regarding each of the pixels, the integer portion of the calculated quantization error not including the decimal portion; and an error diffusion component that generates a correction value by diffusing the quantization error stored in said buffer, wherein the correction value to be added to the bit-connected image data of the target pixel in said correction component is generated by said error diffusion component based on the calculated quantization errors of neighboring pixels of the target pixel stored in said buffer and diffusion coefficients being smaller than 1.0.