Abstract: An encoding method is described for image bitplanes whereby an arithmetic coder using conditioning contexts based on pixels from both the current bitplane and previously decoded bitplanes is employed. For the same number of contexts (which is important for minimizing memory usage), the method provides for higher compression than those methods based on a single bitplane context. An additional improvement over the prior art is that the method eliminates the need to form a Gray code bit plane representation, as is commonly done to reduce the correlation among bit planes. However, if used on conjunction with the gray code, a small improvement in compression performance will still be realized.

Abstract: The K most frequently occurring symbols in an image represented by an alphabet of N symbols are mapped to a set of K codewords. The length of each codeword is an inverse function of the frequency of occurrence of the corresponding symbol in the image and the longest codeword is of length d bits. The remaining N-K symbols are mapped in order of their magnitude to a set of supplementary codewords of a uniform maximum length D bits. The d most significant bits of each supplementary codeword form a prefix which is uniform within each set and specifies whether the corresponding symbol is positive or negative. The remaining or least significant D-d bits of each supplementary codeword comprise a suffix and are mapped in order of bit position to progressively more narrow ranges of symbol values of the remaining N-K symbols.

Abstract: An image processing method is described for the hierarchical storage and display of high resolution digital images in a multiuse environment. The method makes reduced resolution versions of the original image available for quick display on video monitors while providing access to the full resolution image for photographic quality hardcopies. This multiresolution method also provides for the efficient storage of this data via a hybrid coding scheme based on residuals. Several embodiments of this approach are described.

Abstract: An image processing method is described for the hierarchical storage and display of high resolution digital images in a multiuse environment. The method makes reduced resolution versions of the original image available for quick display on video monitors while providing access to the full resolution image for making photographic quality hardcopies. This multiresolution method also provides for the efficient storage of the data resulting from the use of this method via a hybrid coding scheme. Several embodiments of the method are described.

Abstract: An image processing method is described for the hierarchical storage and display of high resolution digital images in a multiuse environment. The method makes reduced resolution versions of the original image available for quick display on video monitors while providing access to the full resolution image for photographic quality hardcopies. This multiresolution method also provides for the efficient storage of this data via a hybrid coding scheme based on residuals. Several embodiments of this approach are described.

Abstract: A method of making a thin lens having a desired high order curvature includes the steps of providing a layer of transparent photoresist; generating a continuous tone exposure pattern for exposing the photoresist such that when exposed and developed the layer of photoresist will possess the desired high order curvature; exposing the layer of photoresist; and developing the layer to produce the thin lens.