Surface inspection system with misregistration error correction and adaptive illumination

An optical surface inspection system is designed to correct for misregistration errors. A reference vector of data samples is obtained by computing an average of adjacent data sample vectors. A comparison of the data samples in a current vector being processed to data samples that may be offset from such current vector along the direction of the current vector enables the detection and correction of misregistration errors. Alternatively, a target array of data samples is compared to a reference array of data samples collected from a different portion of the surface with various offsets for detection and correction of misregistration errors. The intensity of the reflection from the inspection beam may be monitored to vary the intensity of the inspection beam so as to reduce the dynamic range of background scattering.