Image processing apparatus and method

Claim 2

Image processing apparatus as claimed in claim 1 wherein said determining means comprises means for counting said pels having one of the two possible values associated therewith with the sampling pattern (21) at a number of positions with respect to the input image and means for comparing the counted numbers of pels to determine the position at which the counted number is a maximum.

Claim 3

Image processing apparatus as claimed in claim 1 or claim 2 wherein the sampling windows (25A, 25C) are arranged in rows and columns to form the sampling pattern (21), the determining means comprising: means for determining, along the column direction, a position for the sampling pattern (21) such that the sum of the number of pels having said one of the values associated therewith falling in a predetermined portion of each row of the sampling pattern is maximised; means for determining, along the row direction, a position for the sampling pattern such that the sum of the number of pels having said one of the values associated therewith falling in a predetermined portion of each column of the sampling pattern is maximised.

Claim 4

Image processing apparatus as claimed in claim 3 wherein said binary input image is an image of a character and wherein said sampling pattern (21) substantially covers said character, the apparatus including; means for detecting rows and/or columns having a greater number of pels having said one of the values associated therewith than the rows and/or columns adjacent thereto; means for determining an optimum position, with respect to the input image, for each said detected row and/or column such that the number of pels having said one of the values associated therewith falling into at least a portion thereof is maximised, the assignment of grayscale values for the sampling windows (25A, 25C) comprising said detected rows and/or columns being made with said rows and/or columns at their respective optimum positions, the assignment of grayscale values for sampling windows (25A, 25C) comprising other rows and/or columns being made at said determined position for the sampling pattern.

Claim 6

A method as claimed in claim 5 for generating a low resolution grayscale pattern representing a high resolution original character image comprising steps of: generating a sampling pattern having plural sampling windows arranged in columns and rows, the number of said columns and rows being determined by a ratio of said low resolution to said high resolution; in which the determining step comprises sequentially positioning (32, 33) said sampling pattern at plural positions separated by a predetermined distance along a column direction and a row direction on said original character image to count, at each position, the total number of black pels of all rows which is a sum of the number of black pels in a predetermined portion of each row and the total number of black pels of all columns which is a sum of the number of black pels in a predetermined portion of each column of said sampling pattern; comparing (34) the total number of black pels counted at each of said positions to detect a position in a row direction at which the largest total number of black pels of said all columns is detected and a position in a column direction at which the largest total number of black pels of all said rows is detected; positioning said sampling window at said detected position on said original character pattern; and counting (36) the number of black pels in each sampling window of said sampling pattern to assign one of different grayscale values to each sampling window.

Claim 7

A method as claimed in claim 6, wherein a group of pel lines located at a centre portion of said sampling window is used to count the number of black pels in said row and column.

Claim 8

A method as claimed in claim 6 or claim 7, wherein said sampling pattern is sequentially positioned at plural positions separated by one pel line.