Patent ID: 7948657
Filing Date: 2011-05-24
Classification: H04N

Abstract:
1. An image processing method for deciding quantization data on each image plane of image data composed of at least first and second image planes, comprising: an obtaining step of obtaining a sum total value of a first pixel value of the first image plane and a second pixel value of the second image plane, the first and second pixel values existing at the same position on the first and second image planes; a quantization step of performing a quantization process according to an error diffusion method for the sum total value, using a first threshold, and deciding a first quantized value; a selection step of selecting one of the first pixel value of the first image plane and the second pixel value of the second image plane to output a selected value; and a generation step of generating a second quantized value of the first image plane and a third quantized value of the second image plane, the second quantized value and the third quantized value being based on a comparison result between a second threshold and a differential value, the differential value being a difference between the first quantized value and an additional value, the additional value being generated by adding of the selected value and an error that has been derived from peripheral pixels, and generating a diffusing error derived from the generation of the second quantized value and the third quantized value to peripheral pixel positions, wherein the number of levels of the first quantized value is larger than that of the second and third quantized values.