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FIGURE 10. Simplified illustration of filtering process. (A) Model (128 x 128 pixels). (B) Image obtained after backprojection of 128 projections. (C) Low-frequency component of image presented in B. Only overall aspect of image is visible. (D) High-frequency component of image presented in B. Edges are emphasized. Dark rings correspond to negative pixel values. Sum of images in C and D yields image in B. (E) Images in C and D are added, but after C is given low weight to reduce amplitude of low-frequency component.
