Abstract An apparatus for altering the spatial frequency content of recorded patterns by selectively filtering the patterns after they are transformed into the Fourier domain. The filter characteristics are spatially and temporally variable while the real space image of the altered pattern is being observed. A laser beam is projected through a transparency containing the pattern. The patterned beam, with diffraction interference effects, is transformed to the Fourier domain at the surface of a liquid crystal light valve responsive to a spatially and temporally varying light projector. The projector activated regions reflect areas of the Fourier domain beam, while other areas are absorbed or incoherently reflected. A beam splitter redirects a portion of the reflected beam to a continuously observable image plane after transformation back into real space.
An apparatus for selectively and dynamically filtering the spatial frequencies in a pattern, comprising: a means for generating a collimated beam of coherent light; a means for creating a diffraction pattern in said beam; a Fourier transform lens system in the path of said patterned beam; a dynamic means for spatially and temporally varying the reflective characteristics of a surface at the focal plane of said Fourier transform lens system, said dynamic means having a continuously reflective area at the point corresponding to zero spatial frequency; and a means for redirecting the light, reflected off the surface of said dynamic means, onto an image plane.
Claim 2
Independent Claim
105 words
An apparatus for selectively and dynamically filtering the spatial frequencies in a pattern, comprising: a means for generating a collimated beam of coherent light; a means for creating a diffraction pattern in said beam; a Fourier transform lens system in the path of said patterned beam; a dynamic means for spatially and temporally varying the reflective characteristics of a surface at the focal plane of said Fourier transform lens system, said dynamic means having a continuously reflective area at the point corresponding to zero spatial frequency; and a means for redirecting the light, reflected off the surface of said dynamic means, onto an image plane.