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A simplified integer cosine transform and its application in image compression
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Tong, K. Costa, M. |
| Copyright Year | 1994 |
| Description | A simplified version of the integer cosine transform (ICT) is described. For practical reasons, the transform is considered jointly with the quantization of its coefficients. It differs from conventional ICT algorithms in that the combined factors for normalization and quantization are approximated by powers of two. In conventional algorithms, the normalization/quantization stage typically requires as many integer divisions as the number of transform coefficients. By restricting the factors to powers of two, these divisions can be performed by variable shifts in the binary representation of the coefficients, with speed and cost advantages to the hardware implementation of the algorithm. The error introduced by the factor approximations is compensated for in the inverse ICT operation, executed with floating point precision. The simplified ICT algorithm has potential applications in image-compression systems with disparate cost and speed requirements in the encoder and decoder ends. For example, in deep space image telemetry, the image processors on board the spacecraft could take advantage of the simplified, faster encoding operation, which would be adjusted on the ground, with high-precision arithmetic. A dual application is found in compressed video broadcasting. Here, a fast, high-performance processor at the transmitter would precompensate for the factor approximations in the inverse ICT operation, to be performed in real time, at a large number of low-cost receivers. |
| File Size | 555514 |
| Page Count | 11 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19950010871 |
| Archival Resource Key | ark:/13960/t1vf1rn3r |
| Language | English |
| Publisher Date | 1994-11-15 |
| Access Restriction | Open |
| Subject Keyword | Numerical Analysis Integers Data Compression Receivers Error Detection Codes Binary Data Cosine Series Telemetry Decoders Real Time Operation Deep Space Network Transmitters Algorithms Coding Low Cost Video Compression Broadcasting Floating Point Arithmetic Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
