Browse Prior Art Database

Scalable JPEG-Based Compression of Image Data

IP.com Disclosure Number: IPCOM000108192D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Feig, E: AUTHOR [+3]

Abstract

A progressive JPEG encoding scheme with scalable non-JPEG decoding is proposed. This enables a broad range of decoders from low-end all-software to high-end special-purpose hardware-driven devices, with scalable outputs depending on the bandwidth and horsepower of the decoding instrument.

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Scalable JPEG-Based Compression of Image Data

      A progressive JPEG encoding scheme with scalable non-JPEG
decoding is proposed.  This enables a broad range of decoders from
low-end all-software to high-end special-purpose hardware-driven
devices, with scalable outputs depending on the bandwidth and
horsepower of the decoding instrument.

      Data is encoded in progressive JPEG mode, with zig-zag pattern
partitioned so that first the (0,0) or DC component is coded, then
the pair (0,1) and (1,0) or first AC-diagonal, then the triplet
(0,2), (1,1),(2,0) or second AC-diagonal, etc.

      Decoding is done with k X k blocks, with k < 8. A preferred
embodiment takes k=3 and decodes the DC coefficients and the first
two AC-diagonals.  It then performs the descaling and inverse 3 X 3.
DCT on each block, with the remaining AC-coefficients below the
second AC-diagonal set all to 0.

      A second preferred embodiment takes k=4 and decodes the DC
coefficients and the first two AC-diagonals.  It then performs the
descaling and inverse 4 X 4 DCT on each block, with the remaining
AC-coefficients below the second AC-diagonal set all to 0.

      A third preferred embodiment takes k=4 and decodes the DC
coefficients and the first three AC-diagonals.  It then performs the
descaling and inverse 4 X 4 DCT on each block, with the remaining
AC-coefficients below the second AC-diagonal set all to 0.

      More generally, a preferred embodiment takes k < 8 and...