Coded data generation or conversion – Digital code to digital code converters
Patent
1995-08-31
1997-10-14
Young, Brian K.
Coded data generation or conversion
Digital code to digital code converters
358433, H03M 730
Patent
active
056776896
ABSTRACT:
The present invention is a fully JPEG compliant two-pass approach that can compress an arbitrary image to a predetermined fixed size file. The compression coding device and method according to the present invention estimates an activity metric based on the average sum of the absolute value of the quantized DCT coefficients per block. Given the activity metric, a mathematical model relating the image activity to the JPEG Q-factor for a given value of the target compression ratio provides an estimated Q-factor value that yields the design target ratio. This mathematical model is developed during a calibration phase which is executed once off line for a given image capturing device. The fact that our activity metric is based on the quantized DCT coefficients allows for an efficient implementation of the presented coding method in either speed or memory bound systems.
REFERENCES:
patent: 5293252 (1994-03-01), Kim et al.
patent: 5341318 (1994-08-01), Balmanski et al.
Nakagawa, et al., "DCT-Based Still Image Compression ICS with Bit-Rate Control", IEEE, 1992, pp. 711-717.
Wen-Hsiung Chen and William K. Pratt, "Scene Adaptive Coder", IEEE Transactions on Communications, vol.-Com. 32, No. 3, Mar., 1984, pp. 225-232.
Siu-Wai Wu and Allen Gersho, "Rate-Constrained Picture-Adaptive Quantization for JPEG Baseline Coders", 1993, IEEE, pp. V-389-V392.
Abbas Razavi, Rutie Adar, Isaac Shenberg, Rafi Retter, and Rami Friedlander, "VLSI Implementation of an Image Compression Algorithm with a New Bit Rate Control Capability", 1992, IEEE, pp. V-669-V-672.
Kannan Ramchandran and Martin Vetterli, "Rate-Distortion Optional Fast Thresholding with Complete JPEG/MPEG Decoder Compatibility", IEEE Transactions on Image Processing, vol. 3, No. 5, Sep., 1994, pp. 700-704.
Terminal Equipment and Protocols for Telematic Services, Information Technology--Digital Compression and Coding of Continuous-Tone Still Images-Requirements and Guidelines, ISO/TECV-10918-1; 1993(E).
Drukarev Alexander I.
Yovanof Gregory S.
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