| 摘要 |
Apparatus for comparing two patterns translated into electronic data streams, one pattern being a Reference Pattern with which the other pattern, an Inspection Pattern, is to be compared, comprises means for reading each of the patterns pixel by pixel and includes comparison means for comparing a Reference Pattern pixel with a plurality of adjacent pixels in the Reference Pattern to determine the presence or absence of edges, means 80 for comparing pixels of the Reference Pattern with nominally corresponding pixels of the Inspection Pattern to determine whether or not the pixels are the same, and alignment means 81 for automatically incrementing or decrementing the coordinates of the pixels of the Inspection Pattern to compensate for discrepancies between edges in the Reference Pattern and nominally corresponding edges in the Inspection Pattern thereby to bring the two patterns into effective alignment. Two pcb's on adjacent flat beds may be scanned automatically by respective cameras mounted on a common X-Y transport system. <IMAGE> |
