Restored impulse response of finite-range image deblurring filter.
In the absence of noise, a linear spatially invariant blur is completely removed by the application of a transfer function proportional to the inverse of the blur transfer function. However, most blur transfer functions of interest either contain zeros or approach zero; and, consequently, the inverse should cover an infinite dynamic range. In these cases, the inverse can be approximated by a holographic spatial filter that employs a finite range of amplitude transmittance. The effect of finite range on the restored impulse response or point spread function of the combined blurring and deblurring operations are studied. A computer simulation is compared with experimental results for the case of severe defocusing through a circular aperture. (auth)