US 6,333,998 B1 · Image processing method and apparatus

Abstract

Disclosed are an image processing method and apparatus capable of improving character quality by applying smoothing processing even in a case where a faint character image is binarized. A multilevel digital image signal from an image input unit is binarized by a binarizing processor and the resulting bilevel image signal is delayed by a delay circuit for as long as required for pattern matching. Using the bilevel image signal from the delay circuit and the latest bilevel image signal, and in accordance with the predetermined size of a matrix for pattern matching, a pattern matching unit performs pattern matching between the bilevel image signal and all reference patterns stored in a ROM. If a match between the bilevel image and one reference pattern is obtained by pattern matching processing, a pixel substitution processor goes to the ROM to read out a pixel substitution pattern that corresponds to the reference pattern for which the match was obtained and outputs this pixel substitution pattern to an image signal output unit. If a line image in the bilevel image has been rendered discontinuous by an amount equivalent to one or more pixels owing to binarization, the pixel substitution pattern that has been read out and output will make the line continuous to improve the quality of a character image.

Claims31

Dependent claims

An image processing apparatus comprising:

input means for inputting a multilevel digital image signal;
binarizing means for converting the multilevel digital image signal input from said input means to a bilevel image;
pattern storage means for storing predetermined reference patterns and pixel substitution patterns corresponding to the reference patterns;
pattern matching means for comparing the bilevel image and the reference patterns stored in said pattern storage means;
and
pixel substitution means which, if the result of the comparison performed by said pattern matching means indicates that the bilevel image matches a reference pattern, outputs a pixel substitution pattern, which corresponds to this reference pattern,
wherein, the reference patterns are patterns for detecting a case where a line in the bilevel image has been rendered discontinuously by one or more pixels as a result of binarization performed by said binarizing means, and the pixel substitution pattern, which has been stored in said pattern storage means, that is output by said pixel substitution means, are pixel substitution patterns for rendering continuously the line in the bilevel image.

4 more elements

Dependencies are inferred from the claim text.

Image processing method and apparatus

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Image processing method and apparatus

Life of this patent

Abstract

Claims31