FILTER FOR LASER GAGING SYSTEM

A filter for a laser gaging system that significantly increases the accuracy of the system when measuring scattering or translucent surfaces by reducing deviations caused by skewed speckle patterns. The filter limits the field of view of the sensor to light rays originating along the detection axis of the laser gaging system, thereby reducing the effects of noise such as halos, star patterns and beat patterns. The filter can comprise a slit filter or preferably a slit filter in combination with a grated filter, such as a tandem holographic filter.