Digital image deblurring by nonlinear homomorphic flltering

Abstract: This dissertation is concerned with the digital estimation of the frequency response of a two-dimensional linear system through which images have been passed and blurred. Almost no a priori knowledge concerning the system is required, and only one blurred image is necessary for a successful estimation. For those blurs that have phase reversals, such as motion blurs and out-of-focus blurs, a simple method of calculating the correct phase has been developed. A nonlinear homomorphic restoration system is developed and demonstrated on various types of blurred images. An image may be restored by filtering either the intensity version or the density version of the image. The latter not only insures a positive result but also permits simultaneous deblurring and contrast enhancement. The restoration procedure consumes only a modest amount of computation time.