Bending angle detection device and device for detecting a straight line and device for setting a bending angle detection position

摘要

PCT No. PCT/JP94/00773 Sec. 371 Date Aug. 31, 1994 Sec. 102(e) Date Aug. 31, 1994 PCT Filed May 12, 1994 PCT Pub. No. WO94/27756 PCT Pub. Date Dec. 8, 1994In bending angle detection, a linear projected light image formed on the surface of a workpiece is photographed by a photographing device; the actual inclination angle of a specimen is stored as data in correspondence with the inclination angle and position of the specimen in an image; and the bending angle of the workpiece is obtained by accessing the data, with the inclination angle and position of the linear projected light image in an image produced by photographing. In main straight line extraction, main pixels are obtained from the distribution of the brightness of pixels aligned on specified axes and a main straight line is obtained from a plurality of main pixels. For extracting only a necessary straight line from an image including unnecessary straight lines, the photographing device is so disposed as to photograph a lower bender and a second straight line from the bottom end of the image is extracted. In setting a bending angle detecting position, a potential bending step where the bending angle detection of the workpiece might be performed is calculated from simulation data on the bending state of the workpiece in each bending step.