EDGE DIRECTION MEASURING METHOD OF DIGITAL PICTURE

摘要

PURPOSE:To improve the measuring accuracy by obtaining previously a system error and the sub-pixel position of an edge when the edge direction is obtained from a digital picture and then correction the system error for the data obtained from an actual picture. CONSTITUTION:A correction table for system errors is obtained by an experiment for each sub-pixel position of an edge as a preparatory process in regard of a TV camera and a differential operator which are actually used. Then the edge direction and the edge sub-pixel position are measured for an actually photographed picture with use of the same TV camera and differential operator used in the preparatory process. The correction value of the edge direction is obtained by the reverse operation with use of a correction table for the corresponding sub-pixel position. Thus the measuring accuracy is improved for the edge direction and then the curvature of an edge picture element train is measured with high accuracy.