Abstract: Printed wiring board testing apparatus comprising means for optically scanning a board to be tested in orthogonal X-Y axes, with each Y-direction scanning a narrow strip w in the X direction. Means for processing the signals provides signals representative of the characteristics of the board along the strip and for storing the signals. Control means causes the scanning means repeatedly to scan the board in Y direction and to step it a predetermined amount in X direction at each scan end until a required board area board has been scanned and the processing means has processed groups of signals. The processing means identifies common areas of each conductive track, so finally the storage means contains information representative of the co-ordinates of a plurality of datum areas and of the datum areas which are interconnected.

Abstract: Apparatus for testing a printed wiring board comprising means for optically scanning a board to be tested in two orthogonal, X-Y axes such that for each scan in the Y direction it scans a narrow strip of the board of predetermined width, w in the X direction. The optical scanning means is arranged to provide n.m discrete signals for each scan in the Y direction, wherein n is a predetermined number of signals representative of characteristics of the board across the width w of the strip (typically 1000) and m is a number dependent upon the dimension of the board to be scanned in the Y direction. Processing means is provided for processing the signals in groups of n'.times.m' where n' is less than or equal to n and m' is less than or equal to m (typically n' and m' are 40) to provide signals representative of the characteristics of the board along said strip and for storing said signals.