Showing papers on "Standard test image published in 1975"

Ghost suppression in image restoration filtering

Abstract: An optimum image restoration filter is described in which provision is made to constrain the spatial extent of the restoration function, the noise level of the filter output and the rate of falloff of the composite system point-spread away from the origin. Experimental results show that sidelobes on the composite system point-spread function produce ghosts in the restored image near discontinuities in intensity level. By redetermining the filter using a penalty function that is zero over the main lobe of the composite point-spread function of the optimum filter and nonzero where the point-spread function departs from a smoothly decaying function in the sidelobe region, a great reduction in sidelobe level is obtained. Almost no loss in resolving power of the composite system results from this procedure. By iteratively carrying out the same procedure even further reductions in sidelobe level are obtained. Examples of original and iterated restoration functions are shown along with their effects on a test image.

Quasi-real time improvement in small format images

Abstract: A novel image processing technique simulating mechanisms of the human visual system is described. An experiment is detailed, applying the principles of this technique to the digital manipulation of a defocused 35 mm image, and shows the spatial frequency improvement in the resolution of a processed image over the original. The design of a quasi-real time electronic system to rapidly process degraded images in quick succession is discussed.