Apparatus for compression using reversible embedded wavelets
AssigneeRicoh Company, Ltd.
InventorsAhmad Zandi, James D. Allen, Edward L. Schwartz, Martin Boliek
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Abstract
A method and apparatus for encoding and decoding data is described. The present invention includes a method and apparatus for generating transformed signals in response to input data. In one embodiment, the transformed signals are generated using a reversible wavelet transform. The present invention also includes a method and apparatus for compressing the transformed signals into data representing a losslessly compressed version of the input data. In one embodiment, the present invention decomposes the input data using a non-minimal length reversible filter. The decomposition may be performed using multiple one-dimension filters.
Claims29
A coder for encoding a plurality of data symbols comprising:
- a wavelet transform;
- a formatting unit coupled to receive a plurality of coefficients from the wavelet transform and to format the plurality of coefficients into a set of formatted coefficients;
- a magnitude memory coupled to receive the set of formatted coefficients and configured to reorder coefficients in trees into an order based on significance, wherein the magnitude memory comprises
- a plurality of storage areas, wherein each of the plurality of storage areas stores data for a distinct significance level,
- a plurality of counters, wherein each of the plurality of counters is associated with one of the plurality of storage areas and counter values for each of the plurality of counters provide address locations in the plurality of storage areas for storage of the formatted coefficients and are incremented after storing an individual formatted coefficient;
- a significance unit coupled to the formatting unit to generate a plurality of decisions in response to each of the set of formatted coefficients;
- a memory mechanism coupled to receive the plurality of decisions from the significance unit;
- and
- a coder coupled to the memory mechanism and configured to encode data.
A coder for encoding a plurality of data symbols comprising:
- a wavelet transform;
- a sign/magnitude unit coupled to receive a plurality of coefficients from the wavelet transform and to format each of the plurality of coefficients into sign magnitude format;
- a magnitude memory coupled to the sign magnitude unit to reorder coefficients in sign magnitude format into an order based on significance, wherein the magnitude memory comprises
- a plurality of counters;
- and
- a plurality of memories coupled to the plurality of counters, such that each of the plurality of counters is coupled to a distinct one of the plurality of memories, wherein each counter and memory pair is associated with a significance level, such that one of the memories stores each coefficient formatted in sign/magnitude format at a location in said one memory based on an address specified by a count in its associated counter and the count is incremented after an individual formatted coefficient is stored at the location specified by the count;
- a significance unit coupled to generate a plurality of decisions in response to each of the plurality of coefficients being in sign magnitude format;
- a tree memory coupled to receive the plurality of decisions from the significance unit;
- and
- a coder coupled to the memory mechanism and configured to encode data.
Dependencies are inferred from the claim text.