A series of experiments were undertaken to assess the feasibility of defogging color film by the techniques of Optical Spatial Filtering. A coherent optical processor was built using red, blue, and green laser light input and specially designed Fourier transformation lenses. An array of spatial filters was fabricated on black and white emulsion slides using the coherent optical processor. The technique was first applied to laboratory white-light fogged film (Kodak #5386 Ektachrome), and the results were successful. However, when the same technique was applied to some original Apollo X radiation- fogged color negatives, the results showed no similar restoration. Examples of each experiment are presented and possible reasons for the lack of restoration in the Apollo films are discussed.
During winter weather conditions snow and ice can accumulate on railroad traffic signal lenses especially when high efficiency light emitting diodes a...
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United States Department of Transportation
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