US 5,515,180 A · Image processing device

Abstract

The present invention is made to reduce the effect of variation of pulses for driving a printer when recording image data and to improve the gray level representation of picture images to be printed. Data incoming through an image reading device are quantized and processed two pixels at a time by a gray level image processing circuit. The two-pixels' data are first discriminated by an edge discriminator to determine whether they represent an edge portion within the image or not. An object image, on which an operation for inter-pixel spacing shall be conducted, is selected according to the discrimination result. The arithmetic and logic portion performs the above-mentioned operation by two pixels at a time if the data correspond to a non-edge portion and performs correction for enhancement if the data correspond to an edge. This may eliminate the effect of dot displacement due to variation of drive pulses of a printer and improve the quality, in particular, of a gray level image portion.

Claims17

Dependent claims

An image processing device comprising:

image data input means for quantizing image data of an original image;
image data processing means for performing final conversion of the quantized image data;
memory means for storing the converted image data processed by said image data processing means;
and
image data restoring means for restoring the converted image data stored in said memory means and for diffusing errors of the restored image data for gray level representation,
said image data restoring means having arithmetic and logic means for performing operations on inter-pixel spacing for a unit of two or more pixels of the error-diffused restored image data so that inter-pixel spacing between adjacent pixels is constant.

3 more elements

Dependencies are inferred from the claim text.

Image processing device

Life of this patent

Image processing device

Life of this patent

Abstract

Claims17