01-01-2015 дата публикации
Номер: US20150002868A1
Принадлежит:
In the generation of a threshold matrix for N× speed writing, first and second areas are set, the first area being a cluster of a plurality of first partial areas substantially evenly distributed in a matrix space, and the second area being an area of the matrix space excluding the first area. Next, at least two writing elements in each of the first partial areas are allocated occurrence numbers and changed into determined elements. Then, at least one writing element in the second area is allocated an occurrence number and changed into a determined element. Thereafter, the other writing elements are allocated occurrence numbers and changed into determined elements. In accordance with the occurrence numbers, the threshold value of each writing element is determined to obtain a threshold matrix for N× speed writing. This results in a reduction in the graininess of an image in a highlight area. 1. A threshold matrix generation method of generating a threshold matrix for N× speed writing to be compared with a multi-tone original image when said original image is screened into halftone dots for N× speed writing by an image recording apparatus capable of recording an image at 1× speed or at N× speed , where N is an integer of 2 or more , the method comprising:a) preparing a matrix space that is a set of matrix elements arranged in row and column directions, said row direction being perpendicular to said column direction, and said column direction corresponding to a recording direction of said image recording apparatus;b) setting every Nth matrix element aligned in said column direction and every Nth matrix element aligned in said row direction as writing elements and setting the other matrix elements as non-writing elements, said writing elements being matrix elements that correspond to writing positions on a recording object at the time of N× speed writing;c) setting a first area and a second area, said first area being a cluster of a plurality of first partial areas ...
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