Real-time spatial filtering utilizing the piezoelectric-elasto-optic effect

A novel approach to frequency multiplexing of images is presented. By modulating each image pixel at a different (temporal) frequency, the entire image can be transformed into an electrical signal utilizing a single detector. The electrical current of the detector is proportional to the spatial Fourier transform of the image, allowing one to perform spatial frequency manipulations in the time domain. The multiplexing is obtained by using a two-dimensional array of piezoelectric-elasto-optic modulators. By utilizing these effects one makes use of the mechanical resonance of the crystals simplifying the electrical signals needed for excitation. It is shown that a similar (or the same) modulator can be used for image reconstructions; i.e. performing the inverse Fourier transform. Preliminary results obtained with quartz crystals prove the feasibility of this approach.