LOSSY COMPRESSION OF NOISY IMAGES

Noise degrades the performance of any image compression algorithm, Thi s paper studies the effect of noise bn lossy image compression. The ef fect of Gaussian, Poisson, and film-grain noise on compression is stud ied. To reduce the effect of the noise on compression, the distortion is measured with respect to the original image not to the input of the coder. Results of noisy source coding are then used to design the opt imal coder. In the minimum-mean-square-error (MMSE) sense, this is equ ivalent to an MMSE estimator followed by an MMSE coder. The coders for the Poisson noise and the film-grain noise cases are derived and thei r performance is studied. The effect of this preprocessing step is stu died using standard coders, e,g,, JPEG, also. As will be demonstrated, higher quality is achieved at lower bit rates.