Nonlinear filtering in coherent optical systems through halftone screen processes
Hisatoyo Kato, Joseph W. Goodman · Applied Optics · 1975
Nonlinear filtering operations can be performed in coherent optical systems with the help of the halftone screen process. Theoretical and practical considerations regarding this type of system are presented. The use of these methods to achieve logarithmic filtering is emphasized. Applications to separation of multiplicative signals and noise, speckle noise reduction, and processing of radiographic images are considered. Experimental results are presented.