Nec Corporation

Mitsutoshi Arai

Takahiro Hongu

Kouichirou Hirao

Keiji Yamada

Takashi Mochizuki

Toshihiko Okamura

An apparatus for pattern matching encoding includes a pattern extracting unit for extracting patterns in input binary or multi-level image data, an accumulating/match-checking unit for accumulating each extracted pattern and executing a match-check thereof with patterns that have been accumulated, a line segment checking unit for checking each pixel in the match pattern or the extracted pattern as to which line segment in directions the pixel is positioned on, and an encoding unit for encoding the extracted pattern by selecting a template having an optimum form according to the result of the line segment checking. The codes in pattern matching encoding are reduced, and the efficiency of code transmission and code accumulation is improved.

Method and apparatus for pattern matching encoding

A dot angle conversion unit converts the dot angle of image data in an image area, separated by a boundary tracing unit , into 0 degree or 45 degrees. An in-mark correlation checking unit determines a dot frequency of the image data whose dot angle has been converted. A mark re-dividing unit generates small-sized marks based on the dot frequency. A match determination unit checks if a library contains a mark that matches the extracted mark. If the library contains a matching mark, the match determination unit outputs both the extracted mark and the matching mark in the library to a match template processing unit

Coding method and coder using pattern matching

Image data is separated to character region and image region in a character/image separating portion ( ). A mark is cut off from the character region by a mark cut-off portion ( ). The image region is inputted to both the mark cut-off portion and an image period determining portion ( ). The image period determining portion determines the period of grid image and dither image in the image region and notifies that period information to the mark cut-off portion. The mark cut-off portion cuts off the mark from an image in accordance with the period information. The mark cut-off by the mark cut-off portion is accumulated in an accumulating portion ( ) for use as a library and it is determined whether or not there is a match library in old libraries by a match determining portion ( ). If the match determining portion determines that there is a match library, it sends both the mark and match library to a coding portion ( ). The coding portion carries out arithmetic coding by using a template for referring to the mark and reference match library at the same time.

Pattern matching coding device using pattern matching and coding method therefor

In a projection means black pixel histograms of a binary stationary image are generated in both the vertical and the horizontal direction. In a text type judgment means, in accordance with these histograms, a determination is made of whether the image is vertical text or horizontal text. Based on the result of this determination, a pattern block extraction means extracts either a column or a row from the image. The block is further projected and divided into smaller blocks. Then projection is again applied to these divided blocks and patterns are extracted by a pattern extraction means. A judgment is made as to whether or not joining of the extracted patterns is to be performed and, if joining is required, they are joined by a pattern joining means and finally the offsets of all the extracted patterns are calculated, whereupon data (of extracted patterns) are sent to a pattern matching process.

Character recognition apparatus and method for recognizing characters

Pattern encoding is carried out by 1) substituting an index data of a registered pattern for a position data in a library with respect to an index data peculiar to each of the extracted patterns, 2) taking a difference between an off-set position data of the extracted pattern and an off-set position data of the registered pattern whereby an off-set position difference data is provided, and 3) encoding the position data and the off-set position difference data and providing an encoded data. A pattern extracting unit obtains the extracted patterns from image data. An accumulating/checking unit accumulates the extracted patterns as accumulated patterns, assigns indexes specific to the accumulated patterns, and checks each extracted pattern by comparison with the accumulated patterns. When an accumulated pattern is found to match the extracted pattern, the accumulating/checking unit provides a position data within a library instead of the index data, and also provides the off-set position difference data. When no pattern is found to match the accumulated pattern libraries, the accumulating/checking unit provides the off-set position data and bit map data of the extracted pattern to the encoding unit. The arrangement enables the reduction in codes in pattern encoding, thus improving the code transmission efficiency.

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Tokyo, Japan

Mitsutoshi Arai