| 摘要 |
PURPOSE:To detect the difference between two pictures in real time, by processing superposition information, which is obtained by shifting two input pictures from each other with the space frequency by a half period, by the high-pass filter. CONSTITUTION:The write optical system, which writes the first and the second pictures P1 and P2 into space light modulating element 1 and consists of polarizers 9 and 3, focusing lenses 10 and 4, half-mirror 11, grid modulating element 5, photodetector 6, and focusing lens 7, and the read optical system, which reads the differential picture between pictures P1 and P2 from space light modulating element 1 and consists of laser beam source 12, collimator 13, polarizing beam splitter 14, Fourier transform lenses 15 and 17, high-pass space filter 16, and output face 18, are arranged as shown in the figure. Stripe-shaped overall transparent electrodes are arranged on both faces of the electro-optical crystal material in grid modulating element 5, and superposition information of two pictures shifted from each other with the space frequency by a half period is obtained by applying the half-wavelength voltage to this element 5 to select the polarization direction of photodetector 6. |
