Toward a robust solution for image coding with easy content access

We address in this paper the issue of content accessibility in compressed images. Under content accessibility we understand the efficiency of regaining the features of content elements that are important for content-based applications in large-scale image databases. It is realistic to expect that current and future databases are likely to store preferably compressed images in order to optimally use the available storage space. At the same time, widely used image compression methods, also including the present (JPEG) and future standards (JPEG 2000), are not explicitly optimized regarding the content accessibility. Consequently, a high computational load in reaching features in compressed images, combined with a large amount of images stored in a database, can negatively influence the interaction with that database. In order to make this interaction more efficient, it is necessary to develop compression methods that besides the classical three optimization criteria (bit rate/complexity/distortion minimization) also explicitly take into account the accessibility of image content. We approach this challenge and propose here a novel image compression method where a good synergy among all four optimization criteria is reached.