Patent ID: 7589783

Claim:
An inspection system comprising: a first inspection tool comprising a first camera, the first camera having a gain value and an offset value set such that the first inspection tool provides an output indicating a first desired average gray value when the first camera is illuminated with a precision light source set at a first light level; and a second inspection tool comprising a second camera matched to the first camera, wherein the first inspection tool comprises a first controller, the first controller configured to: step a light level setting of the precision light source through a plurality of light levels; illuminate a sensor array of the first camera with the precision light source at each of the plurality of light levels; determine an average gray value for the sensor array at each of the plurality of light levels; fit the plurality of light levels and the average gray value at each of the plurality of light levels to a line; compare a slope and an intercept of the line to desired values; and adjust the gain and the offset of the first camera based on the comparison.