Image compression technique with regionally selective compressio

Details Image compression technique with regionally selective compressio Image compression technique with regionally selective compressio

1992-11-17

1994-07-26

Couso, Jose L.

Image analysis

Histogram processing

For setting a threshold

348390, 348418, G06K 936, G06K 946, H04N 712

Patent

active

053332121

ABSTRACT:
An enhancement to a standard lossy image compression technique wherein a single set of side information is provided to allow decompression of the compressed file. Certain portions of the image are selected (either by the user or automatically) for more compression than other portions of the image. A particular embodiment is implemented for use with the JPEG image compression technique. JPEG calls for subdividing the image into blocks, transforming the array of pixel values in each block according to a discrete cosine transform (DCT) so as to generate a plurality of coefficients, quantizing the coefficients for each block, and entropy encoding the quantized coefficients for each block. Techniques for increasing the compression ratio include subjecting each selected block to a low pass filtering operation prior to the transform, subjecting the coefficients for each selected block to a thresholding operation before the quantizing step, subjecting the coefficients for each selected block to a downward weighting operation before encoding them, or, where the entropy encoding uses Huffman codes, mapping coefficients to adjacent shorter codes.

REFERENCES:
patent: 4286256 (1981-08-01), Langdon, Jr. et al.
patent: 4295125 (1981-10-01), Langdon, Jr.
patent: 4463342 (1984-07-01), Langdon, Jr. et al.
patent: 4467317 (1984-08-01), Langdon, Jr. et al.
patent: 4633490 (1986-12-01), Goertzel et al.
patent: 4652856 (1987-03-01), Mohiuddin et al.
patent: 4691329 (1987-09-01), Juri et al.
patent: 4698689 (1987-10-01), Tzou
patent: 4797741 (1989-01-01), Sato et al.
patent: 4805030 (1989-02-01), Tanaka
patent: 4870497 (1989-09-01), Chamzas et al.
patent: 4873577 (1989-10-01), Chamzas
patent: 4903317 (1990-02-01), Nishihara et al.
patent: 4922273 (1990-05-01), Yonekawa et al.
patent: 5014198 (1991-05-01), Umemura
Mark R. Jaworski, "Imaging for Military Communications", Advanced Imaging Military Communications, May 1991, pp. 18, 21.
Connie Guglielmo, "PicturePress compresses in ratios up to 100-to-1", News MACWEEK, Nov. 6, 1990.

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