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JPEG2000

Image Compression Standard

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Advantages of JPEG2000

Eliminates the blocky appearance of theJPEG image standard.

This is because it uses a wavelet transforminstead of the discrete cosine transform(DCT).

In the previous DCT version, blocks of the

image are compressed individually withoutreference to the adjoining blocks.

Using a DWT creates a much smoother image.

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Original

ImageJPEG JPEG2000

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Advantages of JPEG2000

The compression rate is much higher, while

the retention rate is the same, and often,

better resolution is exhibited.20%-200% better than JPEG Standard with

lossy compression

Able to compress lossless with same engine,whereas, JPEG Standard only achieves lossy

compression

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Building JPEG2000

The simplified version of the steps of this

process is illustrated below.

Forward

TransformQuantization

Entropy

Encoding

Inverse

Forward

Transform

Inverse

Quantization

Entropy

Decoding

Source

Image

Reconsturcted

Image

Compressed

Image

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Image Tiling Wavelet TransformForward Transformation

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Original Image Reconstructed Image Without Tiling

Reconstructed Image

With 128X128 Tile With 64X64 Tile

Wavelet

Tansformed

Image

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Quantization

Entropy

encoding

Source

image data

Forward

transformQuantization

Compressed

image data

qb(u,v) = [sign(qb(u,v))]*[floor(abs(qb(u,v))/ b)]

qb(u,v) is transformed Coefficient

b is the quantization step size

One quantization step-size is allowed (Lossless

compression)

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Entropy Encoding

Entropy encoding

Huffman Coding

Arithmetic Coding

Entropy

encoding

Source

image data

Forward

transformQuantization

Compressed

image data

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Quality Parameters

Method of picture quality measurement:PSNR

Peak Signal To Noise Ratio in dB:

Pixel of the image

Pixel of the reconstructed image

Size of the image

Root Mean Squared Error

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References http://en.wikipedia.org/wiki/JPEG_2000

The JPEG 2000 Still Image Compression Standard by

Athanassios Skodras, Charilaos Christopoulos, and Touradj

Ebrahimi IEEE SIGNAL PROCESSING MAGAZINE 1053-

5888/01, Sept 2011. Efficient Rate Control for JPEG2000 Image Coding Y. M.

Yeung, Member, IEEE, and Oscar C. Au, Senior Member, IEEE

TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR

VIDEO TECHNOLOGY, VOL. 15, NO. 3, MARCH 2005.

http://nptel.iitm.ac.in/video.php?subjectId=106106090 (NPTEL

>> Courses >> Computer Science and Engineering >>

Computer Graphics (Video) >> 42 - Digital Image Processing

Image Compression-Jpeg-Enhancements)

http://en.wikipedia.org/wiki/JPEG_2000http://nptel.iitm.ac.in/video.php?subjectId=106106090http://nptel.iitm.ac.in/video.php?subjectId=106106090http://en.wikipedia.org/wiki/JPEG_2000

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