哈工大信息光学Chapter8-6.pdf

幻 灯 片 Chapter 8 1 Analog Optical Information Processing Weimin Sun College of Science Harbin Engineering University 幻 Tiny：微小的 灯 Opaque ：不透明的 片 8-1 2 n An object has a periodic amplitude transmittance described by tA (x ,h) tA (x) 1 where t (x) is shown above. A n The object is placed in the object plane of the optical system shown below, and a tiny completely opaque stop is introduced on the optical axis in the focal plane, blocking only the spot on t he optical axis. n Sketch the intensity distribution observed in the image plane. 幻 Opaque ：不透明的 灯 Reversal：反转 片 Solution： 3 n The opaque stop on the optical axis blocks only the “DC”or constant Fourier component of the object, which is equivalent to subtracting the constant 4/5 from the given amplitude function. n The intensity is found by taking the squared magnitude of this field. n The resulting intensity of the filtered object is shown in the figure above. n Note the reversal of contrast in the image. 幻 灯 片 4 g (x,h) tA (x ) [rect( x ) 1 comb (x ) 4 ] 4