Image processing system enabling real-time output of image signal based

Abstract

A polygon extracting unit divides a screen image into n-level hierarchy in a scan-line shifting direction. The polygon extracting unit then accesses the sort memory and then reads data, from the screen memory, concerning the end points of the polygon corresponding to the value obtained as a result of the sort memory access. Then, the same unit, in the highest-level regions of the hierarchy, extracts the polygon edge-pairs overlapping the highest-level region. Then, the same unit, based on polygon edge-information, calculates the information concerning the corresponding edge pair to appear on the scan line. A polygon-edge-pair memory stores data concerning the starting point and ending point of the polygon on the scan line. A transfer unit determines whether or not the extracted polygon edge-pair overlaps with the relevant region. The same unit then transfers the polygon edge-pair to the lower-level regions if the polygon edge-pair overlaps. A polygon-edge-pair data transfer unit, in the lowest-level region, determines whether or not the polygon edge-pair overlaps with the lowest-level region. The same unit then transfers a parameter required for vertical interpolation from the polygon-edge-pair memory, for the polygon edge-pair, if the polygon edge-pair overlaps. A vertical-interpolation operation unit calculates the gradient of the relevant polygon edge-pair based on the relevant data. The same unit then calculates so as to interpolate between the right crossing point and the left crossing point on the scan line. An output unit outputs dot data synchronized to the scan line associated with display unit for displaying the relevant polygon figure.