Image analysis – Image compression or coding
Reexamination Certificate
2000-06-21
2001-06-19
Couso, Jose L. (Department: 2624)
Image analysis
Image compression or coding
C382S298000
Reexamination Certificate
active
06249611
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the compression and expansion of data and, in particular, to a method and apparatus for compressing and expanding digital data.
BACKGROUND OF THE INVENTION
Advancements in the development of improved signal processing algorithms have resulted in the production of output data with a high output dynamic range (in bits). For example, recently developed adaptive spectral equalization (ASE) and enhanced narrowband processing (ENP) algorithms having increased signal processing data output from a traditional three bits to eight bits. In view of the increased dynamic range of such signal processing algorithms, considerable effort is now being mounted in the development of efficient and effective methods and systems for compressing and expanding data. The key requirements of such compression and expansion systems are: minimal computational horsepower needs; fixed compressed data size for transferring a requisite amount of information; and minimal information loss or generated artifacts resulting from the data compression process. The requirement to minimize the requisite computational horsepower facilitates the use of commercial off-the-shelf computing components, thus reducing system implementation expense by obviating the need for custom hardware to support operational performance requirements. The remaining requirements reflect a balancing of the need to accurately transmit a large amount of information with the need to transmit that information in a minimal amount of space and time.
SUMMARY OF THE INVENTION
The present invention is a method and apparatus for compressing and expanding digital data. The apparatus includes a compressor module for compressing original data and an expander module for expanding the compressed data to substantially recover the original data.
The compressor module includes a reduced resolution data set (RRDS) generator providing a low pass filtering and decimation (down sampling) of the original data. The RRDS generator performs the down sampling in either the time dimension only (resulting in a one-half reduction in data size), or in both the time and frequency dimensions (resulting in a one-quarter reduction in data size). The RRDS generator provides a bypass functionality that, when selected, bypasses the low pass filtering and decimation operation and passes the original data to the output of the generator unaltered. The compressor module further includes a one-dimensional delta pulse code modulation (DPCM) compressor performing either three or four bit encoding on the data output from the RRDS generator. The DPCM compressor includes a compression feedback loop for minimizing the likelihood of compressor deviation.
The expander module includes a DPCM expander performing either three or four bit decoding of the data output from the compressor module. The expander module further includes an RRDS expander providing interpolation (up-sampling) of the expanded data output from the DPCM expander. If bypass of the RRDS generator was previously selected during compression, the expanded data automatically bypasses the RRDS expander and is output unaltered. An edge enhancement filter is also included in the expander module for processing the data output from the RRDS expander to increase signal detectability by correcting for any signal and texture errors introduced by the RRDS generation and RRDS expansion processes.
REFERENCES:
patent: 4303947 (1981-12-01), Stoffel
patent: 4628534 (1986-12-01), Marshall
patent: 4706260 (1987-11-01), Fedele et al.
patent: 4734768 (1988-03-01), Pexa
patent: 4786975 (1988-11-01), Postl
patent: 4829453 (1989-05-01), Katsuta et al.
patent: 4868764 (1989-09-01), Richards
patent: 5048111 (1991-09-01), Jones et al.
patent: 5103306 (1992-04-01), Weiman et al.
patent: 5153936 (1992-10-01), Morris et al.
patent: 5271064 (1993-12-01), Dhawan et al.
patent: 5289548 (1994-02-01), Wilson et al.
patent: 5293432 (1994-03-01), Gonser et al.
patent: 5309526 (1994-05-01), Pappas et al.
patent: 5341442 (1994-08-01), Barrett
patent: 5448654 (1995-09-01), Katayama et al.
patent: 6137922 (2000-10-01), Broussard et al.
Broussard Dane John
Matthews Richard Ray
Baker & Botts L.L.P.
Couso Jose L.
Do Anh Hong
Raytheon Company
LandOfFree
Method and apparatus for compressing and expanding digital data does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for compressing and expanding digital data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for compressing and expanding digital data will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436982