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Method for efficient data preprocessing in a JPEG 2000 encoder and decoder

IP.com Disclosure Number: IPCOM000011525D
Publication Date: 2003-Feb-26
Document File: 4 page(s) / 90K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for efficient data preprocessing in a JPEG 2000 encoder and decoder. Benefits include improved functionality and improved performance.

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Method for efficient data preprocessing in a JPEG 2000 encoder and decoder

Disclosed is a method for efficient data preprocessing in a JPEG 2000 encoder and decoder. Benefits include improved functionality and improved performance.

Background

        � � � � � JPEG 2000 is an image coding system standard published as ISO/IEC 15444-1:2000 ver. 1.0 (released March 16, 2000, see www.jpeg.org). The compressed image is divided into tiles. Each tile is processed through a wavelet transform engine that breaks it into subbands. They are compressed to include a context and data pair that can be streamed serially. The compression is performed using bit planes rather than pixel planes.

        � � � � � To encode an image, conventional processing would load a register with a pixel and perform an AND instruction to mask out a bit. Two operations are required to extract one bit. A 64x64 16-bit pixel code block takes 2*16*64*64 = 131,072 cycles. Checking for zero bit planes uses 2*15*64*64 = 122,880 cycles. A total 253,952 cycles are required to process a 64x64 pixel block.

        � � � � � To decode an image, conventional processing would use three instructions to generate one bit of a pixel. A total 48 cycles are required to generate one pixel.

General description

        � � � � � The disclosed method is efficient data preprocessing in a JPEG 2000 encoder and decoder. The key elements of the method include:

•        � � � � Conversion of pixel planes to bit planes

•        � � � � Compression speed up to one pixel per cycle

•        � � � � Two methods for efficiently converting from pixel format to bit-plane format:

        � � � � � -        � � � � Flash-flush method

        � � � � � -        � � � � Register method

Advantages

        � � � � � Some implementations of the disclosed structure and method provide one or more of the following advantages:

•        � � � � Improved functionality due to support for the JPEG 2000 standard

•        � � � � Improved performance due to the efficient formatting of the pixel coefficient data to/from bit-planes

Detailed description

        � � � � � The disclosed method is efficient data preprocessing in a JPEG 2000 encoder and decoder. A main function block of the method is the bit plane formatter (see Figure 1). The image data in pixels comes in 1’s complement or 2’s complement format. The S-mag converter converts the data into sig...