Hewlett-packard Development Company, L.P.

Hewlett-packard Company

David S Taubman

Erik Ordentlich

Yucel Altunbasak

Christos Chrysafis

Embedded block entropy coding with optimized truncation is useful for image compression schemes in conjunction, for example, with a Wavelet transform, so as to form a bit-stream which can be stored or transmitted with increased efficiency. In the arithmetic coding phase, several opportunities exist for minimizing complexity and improving compression and computational performance as compared to existing systems. One method involves bypassing the arithmetic coding procedure for certain lower significance bit-planes of each code-block. Then, the raw binary digits from these bit-planes can be interleaved into the arithmetically coded bit-stream. As a result, both the average number of arithmetically coded symbols and the maximum number of coding passes per code-block can be significantly reduced.

Block entropy coding in embedded block coding with optimized truncation image compression

A method for operating a data processing system to generate a second image from a first image. The first image includes a two dimensional array of pixel values, each pixel value corresponding to the light intensity in one of a plurality of spectral bands at a location in the first image. The method utilizes a linear transformation of a vector derived from super input pixels to obtain a vector that includes at least one super output pixel. The super input pixels are defined by separating the pixels of the first image into a plurality of input image planes having identical numbers of pixels corresponding to the same spectral band. Each super input pixel is a vector of dimension P, where P is the number of the input image planes. Similarly, a set of output image planes is defined, each pixel in a given output image plane representing the intensity of the second image in one of a plurality of spectral bands at a corresponding point in the second image. Each super output pixel is a vector of dimension Q, where Q is the number of the output image planes, each component of that vector being a pixel from a corresponding output image plane. In the preferred embodiment of the present invention, the linear transformation depends on the properties of the optical system and the illumination source used to generate the first image.

Image demosaicing and enhancement system

An apparatus for recording an image. The apparatus includes a two-dimensional array of image sensors. Each image sensor provides a measurement of the light intensity in a selected spectral region. The two-dimensional array is generated from a plurality of identical blocks of sensors, the blocks being juxtaposed to form the array. Each of the blocks has equal numbers of sensors for each of the spectral regions, the number of different spectral regions being at least three. The sensors in the blocks are arranged in a two-dimensional array having a plurality of rows and columns. The sensors in the blocks are arranged such that any straight line passing through a given sensor also passes through sensors of at least three different colors whose spectral responses are all linearly independent. In the preferred embodiment of the present invention, all three such sensors lie within a disk, centered at the first sensor and having a radius no larger than five times the center to center spacing of the blocks in the sensor array. In the preferred embodiment of the present invention, each of the sensors corresponding to one of the selected spectral regions in blocks not adjacent to an edge of the two-dimensional array is adjacent to a sensor corresponding to the same spectral region.

Image sensor for digital cameras

A multi-layer embedded bitstream is generated from a subband decomposition by partitioning each subband of the decomposition into a plurality of blocks; and encoding the blocks of each subband. The blocks of each subband are coded independently of each other. Resulting is a block bitstream corresponding to each block. Truncation points may be identified on the block bitstreams, and selected portions of the block bitstreams may be concatenated, layer-by-layer, to form the single-layer or multi-layer bitstream. Syntax information may also be added to the multi-layer bitstream. An image can be reconstructed from the embedded bitstream at a desired bit-rate or resolution by reading the syntax information, randomly accessing desired portions of the block bitstreams, decoding the randomly accessed portions, dequantizing the decoded portions, and applying an inverse transform to the dequantized portions.

Embedded block coding with optimized truncation

A subband decomposition of an image is performed by filtering the image in a progression of N line windows. In a first filter stage, vertical filters perform high and low pass filtering on each N line window. Then horizontal filtering is performed on the output of each vertical filter. The lowest subband provided by the filter stage is recursively decomposed by additional filter stages. Higher subbands of each filter stage are encoded and placed in an embedded bitstream. Block encoding can be performed in which a number of lines of each subband are coded as a plurality of blocks. The blocks of a subband are coded independently of each other. The block coding supports region-of-interest reconstruction.

Efficient wavelet-based compression of large images

Hardware resolution of a scanner is increased without improving the quality of the scanner's sensor array or imaging optics. A first low-resolution representation of an image is generated during a first scan and a second low-resolution representation of the image is generated during a second scan. The scanner is configured to intentionally induce a motion error in either the first or second representation. A composite representation of the first and second representations is generated from the first and second representations, and a super resolution technique is used to generate a third representation of the image from the composite representation. The third representation has a higher resolution than the first and second representations.

Apparatus and method of increasing scanner resolution

Motion between two video fields is estimated by obtaining a two-bit representation of each sample in the bandpass filtered fields; determining an initial coarse motion estimate by comparing the two-bit representations which are associated with relatively displaced regions from the two fields; and refining the initial coarse motion estimate to fractional pixel accuracy.

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Pymble, Australia

David S Taubman