Patent ID: 7355193

Claim:
A method of detecting a defect on a surface being scanned, the method comprising: scanning with a first scan an area on the surface with a light source and a first photosensor array; scanning with a second scan the area on the surface with the light source and a second photosensor array; where the light source and first and second photosensor arrays are stationary relative to each other, the first and second photosensor arrays are spaced apart, and where there is relative movement between the light source and the area during the first and second scans and where an angle of the illumination of the first scan is different from the second scan; determining that a defect is present in the area when the first and second scans are different; determining that a defect is present in the area when an apparent shadow in the first scan has a different size in the second scan; creating a composite image from the first and second scans; and searching the composite image for defects, where a defect is associated with a unique pattern of colors that generates a series of overlapping shadows, where each shadow is a different color.