MARK POSITION DETECTION SYSTEM FOR POSITIONING

摘要

PURPOSE:To enable the detection of a position and attitude for mounting a component at a high speed with a single view, by determining coordinate values of a probable edge of a positioning mark by the unit smaller than one pixel to calculate point coordinate values thereof by an average method. CONSTITUTION:A printed circuit board with a positioning mark 2 is taken with a TV camera for detecting positions. The brightness of a measuring line alpha9 is determined when the X-axis is defined along the direction of the TV scanning line within a measuring area 1 and the brightness of a measuring line beta9 is done with that in the Y-axis. A monotonously increasing R1 range and monotonously decreasing range R2 are extracted from the resulting brightness variation curve to determine max. tilt positions M1 and M2 by applying a specified formula to these ranges. This specified formula normalizes the sum of products as obtained from the multiplication of each coordinate value in the covering range by the variation in brightness at the coordinate as weight. Then, the measuring lines are scanned at each train of pixels and the coordinate values determined as edge coordinate values of a mark 2 are averaged whereby the Y-coordinate at the center coordinate of the mark 2 is obtained from the line alpha9 while the X-coordinate from the line beta9. Then, the positions of contact patterns are determined from the positions of plural marks 2.