Verfahren und Vorrichtung zum Ziehen von Konturen eines Bildes

摘要

The present invention provides an improved technique for extracting contours in an image without waiting for processing all the scanning lines on the image. Run-data on two boundary scanning lines, each representing the boundary coordinates at which the image changes, are stored in a run-data buffer. A contour extraction unit compares two sets of the run-data with one another to extract segment vectors and detect a set of closed-loop vectors defining a contour of an image area. Three registers in a working buffer store specific data representing the relationship between a starting point and a terminal point of each vector sequence and are used in detecting closed-loop vectors. A vector data memory stores vector data including coordinate values of start and end points of closed-loop vectors. The contour extraction unit detects a vector sequence which has a starting point identical with a terminal point as a function of the data registered in the working buffer to identify the vector sequence as a closed-loop.