aoterspeglande avlaesning av felaktigheter i that traeds aodring

摘要

Grain defect scanning is accomplished by a pair of lightdetectors directed toward an inspection point illuminated by acollimated light beam incident upon the inspection surface at agiven angle of incidence. one detector, the specular detector, ispositioned along the specular angle of reflection as defined by theangle of incidence and the other detector, the diffuse detector,lies substantially along the angle of incidence. When specularreflection dominates, as when the inspection point corresponds toclearwood, the specular detector indicates a higher reflectivelight intensity than the diffuse detector. When diffuse reflectiondominates, however, as when the inspection point corresponds to agrain defect, both detectors indicate similar reflective lightintensity. Grain defect discrimination is accomplished bycalculating a ratio of specular detector output to diffuse detectoroutput. Further analysis of the relative magnitudes of thedetector outputs provides a basis for identifying grading marks,such as ink and wax marks, at the inspection point.