Intensity-Invariant Joint Transform Correlator
The optical joint transform correlation results from the diffraction of a collimated beam from a prerecorded interference pattern, produced by the Fourier transform of a target and a reference. The joint transform can be seen as the Young interference generated by multiple pairs of point sources separated by the same distance. When the intensities of the target and reference are not identical, the generated Young fringes cannot achieve a unity visibility, and, as a consequence, the final correlation intensity (which is the light diffracted by the recorded fringe pattern) is not a maximum.
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