Abstract: In a multiresolution image processing system images are stored in files that contain thumbnail data as well as a full image data structure. The image data is preferably wavelet or wavelet-like transform coefficients, generated by applying a wavelet or wavelet-like transform to an image multiple times. Data representing mid-level resolution images are generated on the fly by extracting from the full image data structure only the data needed for the user or application selected resolution level. If the user has selected a subset of the image for viewing at a higher resolution level, a corresponding mid-level resolution image is constructed by extracting from the full image data structure the data needed for the user specified image portion at the user or application selected resolution level. The full image data structure is preferably encoded and stored in a manner allowing the image data for mid-level resolution images to be efficiently extracted without having to compute or recompute any image coefficients.

Abstract: A data encoder and method utilizes a node list for storing a list of nodes in the data array to be processed, a branch list for storing a list of tree branches in the data array to be processed and a set list for storing a list of data sets. The method begins by initially storing in the node list node identifiers representing a predefined set of nodes in the data array, corresponding to coefficients generated by a last iteration of a data decomposition procedure. Also, it initially stores in the branch list branch identifiers representing tree branches corresponding to a predefined subset of the nodes initially listed in the node list. Each such tree branch has an associated root node and a branch depth value indicating how many node layers intervene between the root node and the nodes of the tree branch closest to the root node. The set list is initially empty, and a parameter called the LayerLimit value is also initialized.

Abstract: A data encoder and method successively analyzes successively smaller blocks of a specified data array. Data blocks are analyzed in a predefined order, and corresponding entries identifying data blocks containing at least one non-zero value are stored in that same order in a list of blocks. Whenever a data block is processed, if the data block is entirely filled with zero data it is so identified in the output data and no further processing of the subblock is required. Otherwise, if the size of the data block is greater than a predefined minimum block size (e.g., 2.times.2), the block is divided into smaller data blocks and those smaller data blocks are put on the list of blocks for further processing. Finally, if the size of a data block that is being processed is the predefined minimum block size, values representing all the data items in that data block are written into the output data.