Optimizing the performance of wavelet coders by image processing

Pre-processing images prior to encoding can remove noise, or unimportant detail, and thus improve the overall performance of the coder. Typical objective image quality metrics are obtained by computing a single or several numbers as a function of the difference image between the original and coded images. Such metrics may ont reflect the improvement in performance. In a recent paper we have presented a methodology that allows the quantitative determination of image quality when the image has been processed prior to encoding. We now present an extension of the work showing global objective quality measures that quantify the value of pre-processing for image coding using a wavelet coder. Because many options are available in wavelet coder design, we limit our study to a 'best' coder obtained in previous work, and determine what further performance improvement can be achieved by image processing.