Merging images in JPEG2000-domain

Compressed images are often understood as static and indivisible objects. With the advent of scalable compression schemes including JPEG2000 and some modes of the JPEG standard, compressed images may be usefully accessed at reduced quality, resolution, or in selected spatial regions. Nevertheless, the original image remains unchanged. In this paper we are concerned with interactively editing scalably compressed images in the compressed domain. We consider the particular problem of merging regions from two different compressed images, but our method is appropriate also to selectively updating image regions, which may also be used as a means for realizing video transmission through conditional replenishment. The new image coding standard JPEG2000 offers new options for handling compressed raster images, in addition to its superior compression performance. In this paper we propose three different strategies to combine and merge images in the JPEG2000 compressed domain, by exploiting the flexible code-stream syntax of the new standard. Our approach saves computing power and can be used to combine image content in a variety of ways. The resulting code-streams are fully compliant with the JPEG2000 specification.