Patent Document ID: 5537490
Application ID: 08111044
Patent Status: 1

Claim One:
1. A line image processing method for processing an image in which the following defective line or lines exist in a line image to be processed: a line which is connected to another line to make a long line or make a branch line and which should be disconnected therefrom, lines which should be connected to each other and which are separated from each other, a line which is connected to another line which is an unnecessary short line, or a line which is connected to an unnecessary short line which is due to noise, comprising the steps of: receiving a line image to be processed by an image pick-up device; scanning the line image to retrieve a line to be traced, the line having a width of one pixel; tracing a line direction for each pixel composing the retrieved line by means of a direction code; tracing the retrieved and traced line to an end point thereof by selecting at a branch point a direction code closer to an average value of a plurality of various direction codes disposed at points preceding the branch point when the branch point is detected; storing image data of a cluster and erasing an image of the cluster corresponding to the line traced to the end point thereof from the line image to be processed; transferring the stored image data of the cluster to form a processed line image; and tracing all lines by repeating the above steps starting from the scanning step; further comprising, after the step of transferring the image data of the cluster, the steps of: scanning the processed line image so as to retrieve each pair of lines which have end points which are close and opposed to each other; calculating x.sub.1 indicating a distance between end points of each pair of lines, and x.sub.2 indicating an angular difference (.vertline.ed1-ed2.vertline.) between average angular directions of each pair of lines around the end points thereof; finding values of goodness of fit based on the calculated values x.sub.1 and x.sub.2 by utilizing membership functions showing a first fuzzy rule that IF x.sub.1 is small and x.sub.2 is small, THEN the end points are connected to each other and a second fuzzy rule that IF x.sub.1 or x.sub.2 is large, THEN the end points are not connected to each other, and then finding a total value of goodness of fit in the vicinity of the end points of the retrieved pairs of lines; comparing the total value with a threshold and then connecting the retrieved pairs of lines to each other if the total value is within a predetermined range with respect to the threshold; and repeating the above steps to connect all the pairs of lines which should be connected.