Image Processing System For Enhancement And Deblurring Of Photographs

Abstract

This paper describes an image processing system that is in operational use for the extraction of latent information from degraded photographs arising in routine police work. A wide range of spatial domain and Fourier domain techniques to both diagnose and correct for various picture problems are described. The enhancement methods discussed include contrast enhancement, noise filtering, digital color filtering, perspective correction, adaptive Fourier filtering to remove background patterns, and image deblurring. Color images are treated by operating on the separated red, green, and blue (R, G, B) components, and a novel encoding scheme is used to enable the display of color pictures on a standard 8-bit frame store. These techniques have been developed for, and applied to, operational rather than laboratory-generated images. A brief description is given of the hardware that is used, which incorpo-rates an array processor to enhance computational speed, a high quality micro-densitometer for digitizing images, and a digital frame store for final display. The system has been configured to give an operator as much interactive control as possible.