REGION OF IRRADIATION FIELD EXTRACTING DEVICE FOR RADIOGRAPH

摘要

PURPOSE:To extract a region of irradiation field in the case of picking up an image in such a manner that a rectangular irradiation field is diagonal with the edge side of the image or even in the case of picking up the image in the irradiation field of a polygonal shape by extracting the region enclosed by >=1 pieces of the straight lines determined by determining a linear equation of a boundary line as the irradiation field region of radiations. CONSTITUTION:The data of digital radiograph signals are rotationally moved in the position of respective pieces of the image data in the orthogonal coordinate system set longitudinally and transversely along the edge insides of the image around the prescribed center of rotation. Next, whether a straight line considered to be a boundary line of the region of irradiation field and the limited irradiation field is parallel with the X-axis or Y-axis of the orthogonal coordinates or not is decided. The linear equation before rotation of the straight component is calculated form the distance form the center of rotation and the rotating angle when that this straight line component is parallel therewith is decided. The region on the inner side enclosed by >=1 pieces of the calculated straight line is extracted as the irradiation field region by utilizing the linear equation for these straight lines.