Method of tracing contour and a system therefor
First Claim
1. A method of tracing a contour to obtain contour coordinates by extracting segments of a contour of a figure from a sampled image, comprising the steps of:
- scanning said figure along sequential scanning lines in a single scanning direction;
detecting at least one image transition point for each sequential scanning line through said figure;
extracting segments of the contour of the figure by comparing a detected relationship between the position of an image transition point of each scanning line and the position of an image transition point of the adjacent preceding scanning line to a plurality of basic patterns representing different positional relationship and selecting a basic pattern corresponding to each detected relationship along the contour of the figure;
combining selected basic patterns into a basic pattern sequence on the basis of the positions of the detected image transition points; and
converting said basic pattern sequence into a sequence of contour coordinates.
1 Assignment
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Accused Products
Abstract
A system for tracing contour to prepare contour coordinates by tracing contour lines of a figure from an image that consists of a set of a plurality of lines, comprising a memory stored in advance from a basic pattern related to figure contour lines of positions of image transistion points between the neighboring two lines. An image transition point of a line is detected and another image transition point of a line that precedes the above line is detected, too. A pattern of image transistion points of the above two lines is extracted based upon the basic pattern. The thus extracted basic patterns are then integrated and are converted into contour coordinates.
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Citations
8 Claims
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1. A method of tracing a contour to obtain contour coordinates by extracting segments of a contour of a figure from a sampled image, comprising the steps of:
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scanning said figure along sequential scanning lines in a single scanning direction; detecting at least one image transition point for each sequential scanning line through said figure; extracting segments of the contour of the figure by comparing a detected relationship between the position of an image transition point of each scanning line and the position of an image transition point of the adjacent preceding scanning line to a plurality of basic patterns representing different positional relationship and selecting a basic pattern corresponding to each detected relationship along the contour of the figure; combining selected basic patterns into a basic pattern sequence on the basis of the positions of the detected image transition points; and converting said basic pattern sequence into a sequence of contour coordinates. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for tracing a contour to obtain contour coordinates by extracting segments of a contour of a figure from a sampled image, comprising:
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means for scanning said figure along sequential scanning lines in a single scanning direction; means for detecting at least one image transition point for each sequential scanning line through said figure; means for extracting segments of the contour of the figure by comparing a detected relationship between the position of an image transition point of each scanning line and the position of an image transition point of the adjacent preceding scanning line to a plurality of basic patterns representing different positional relationships and for selecting a basic pattern corresponding to each detected relationship along the contour of the figure; means for combining selected basic patterns into a basic pattern sequence on the basis of the positions of the detected image transition points; and means for converting said basic pattern sequence into a sequence of contour coordinates. - View Dependent Claims (8)
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Specification