1. An optical surface inspection apparatus for determining the presence of unknown surface conditions on a target surface, comprising: illumination means for generating an incidence light beam; scanning means for scanning the light beam across the target surface, whereby the target surface scatters light in the presence of the light beam; light collection means for collecting scattered light, said light collection means comprises: (a) detector means for detecting light; (b) a dynamic reflective spatial attenuator receiving scattered light from the target surface; (c) control means for controlling the dynamic reflective spatial attenuator to obtain an attenuation pattern that selectively diverts light to the detector means; discriminating means for determining the presence of unknown surface conditions based on the light detected by the detector means.