Coherent optical feature identifier apparatus

Claim 1

An optical correlator for identifying features on a photographic film comprising in combination: means for generating a source of coherent light, said coherent light being non-divergent, means for focusing said coherent light through said photographic film, said photographic film including an index of refraction matching means attached to said photographic film, a spatial filter disk in alignment with and interacting with said focusing means, said spatial filter disk comprises a glass disk with a plurality of wedge sections inscribed thereon, each wedge section of said plurality of wedge sections being divided into a plurality of linearly decreasing sub-regions, each sub-region having a discrete emulsion deposition that is characteristic of a particular feature, a Fourier Transform lens between said means for focusing coherent light and said spatial filter disk, said spatial filter disk having a Fourier Transform power spectra emulsion deposited thereon, said spatial filter disk providing an optical correlation signal in response to the coincidence of a photographic film feature and a corresponding filter disk Fourier Transform power spectra feature, and, means for detecting said optical correlation signal positioned in alignment with said spatial filter disk, said detecting means providing an analog signal in response to said optical correlation signal.