摘要 |
<p>An apparatus (10) for inspecting the surface of an object S moving in the direction of travel (23) relative to the apparatus comprises a modular sensing head assembly (11) including a plurality of sensing head modules (12, 13), each of which includes a number of sensing stations (16 - 21). Each sensing station includes a light source (77, 81, 84) for generating a line of light extending across substantially the width of the surface of the object and a plurality of optical detector means for detecting light scattered from the line of light by the surface of the object. The optical detectors are positioned and oriented to receive scattered light scattered along paths lying in detection planes which are perpendicular to each other and perpendicular to the surface of the object. Signal processing electronics are provided to convert the light received by the detectors into analog signals which are multiplexed, converted to digital signals, filtered and then compared to preselected thresholds to determine the existence of any defects in the surface.</p> |