| 摘要 |
To determine the position of a bend in a workpiece, a flat beam of light is projected onto the workpiece, the resulting line S on the workpiece is imaged, windows W4-W7 are set on the straight portions S1,S2 of the line, equations of lines L1,L2 through the centres of gravity of the portions in the windows are determined, and their crossing point Q identifies the position of the bend. To overcome halation H, a reference point M used for setting the positions of windows is determined by first setting a window extending in the Y direction on each line portions S1,S2 at a predetermined distance behind the front endmost point of the line image. M is the point centrally between the centres of gravity of the imaged portions in these windows. To overcome unwanted reflections R, the area furthest in the X-direction is chosen to set the position of the Y-directed windows and to determine the centre of gravity in each windows W4-W7. |
