Matched Spatial Filtering Using a Reflection-type Volume Hologram

Matched spatial filtering with a reflection-type volume hologram has been investigated theoretically and experimentally. Two effects of a volume hologram are considered: the distortion of the correlation image due to the reduction in the hologram thickness, and the narrow wavelength selectivity of the reflection hologram for temporally incoherent illumination. Two kinds of blur in correlation detection are described when the hologram is illuminated with white light. Experimental results of character recognition using a pressure-broadened, mercury-light illumination without an interference filter are given.