Patent ID: 6775027
Filing Date: 2004-08-10
Classification: H04N

Abstract:
An image processing apparatus, comprising:an error adding portion which adds together input multi-tone image data and peripheral error information; an adding/subtracting portion which adds to or subtracts from multi-tone image data calculated by said error adding portion a random number in a matrix prepared for each set of pixels of the input multi-tone image data; a quantizing portion which quantizes multi-tone image data calculated by said adding/subtracting portion into image data, the number of bits of which image data being smaller than the number of bits of the multi-tone image data calculated by said adding/subtracting portion; an error calculating portion which calculates an error based on the multi-tone image data calculated by said error adding portion and the image data quantized by said quantizing portion; an error storing portion which stores the error calculated by said error calculating portion for each peripheral pixel; and an error operation portion which calculates the peripheral error information based on the errors stored in said error storing portion for respective peripheral pixels, and provides the peripheral error information to said error adding portion.