International Telecommunication Union
JPEG 2000
A versatile image coding
system for multimedia
applications
Touradj Ebrahimi
EPFL
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
Why another still image compression
standard?
ITU-T
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Low bit-rate compression
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Lossless and lossy compression
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Computer generated imaging
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Transmission in noisy environments
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Compound documents
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Flexible progressive coding and random access
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ITU-T VICA Workshop
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Markets and Applications
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Internet
Mobile
Printing
Scanning
Digital Photography
Remote Sensing
Facsimile
Medical
D-Cinema
Digital Libraries
E-Commerce
Space imaging
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Markets and Applications
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Non-native software
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JPEG 2000 family
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Part1: Core Coding
System
Part3: Motion
JPEG2000
Part5: Reference
Software
Part2: Extensions
Part8: JPSEC
(Secure JPEG2000)
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Part4: Conformance
Testing
Part9: JPIP
(Interactivity)
Part10: JP3D
(3-D Extensions)
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
Part6: Compound
Image
File Format
Compound
Part11: JPWL
(Wireless)
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JPEG 2000 part I
ITU-T
¾ A set of tools covering a good proportion of application
requirements (20-80 rules)
¾ Royalty fee-free, license-fee free (doesn’t mean IPR free)
¾ Other parts are derived as extensions with backward
compatibility to part I (baseline)
¾ Reached International Standard status on Dec. 2000
¾ Amendments have been defined since (one for D-cinema under
progress)
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Features in Part I
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High compression efficiency
Lossless colour transformations
Lossy and lossless coding in one algorithm
Embedded lossy to lossless coding
Progressive by resolution, quality, position, …
Region-of-Interest coding/decoding
Error resilience coding
Perceptual quality coding
Multiple component image coding
Tiling
Palletized image coding
Light file format (optional)
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Comparison of various algorithms
from a functionality point of view
ITU-T
JPEG 2000 JPEG-LS
lossless compression performance
lossy compression performance
progressive bitstreams
Region of Interest (ROI) coding
arbitrary shaped objects
random access
low complexity
error resilience
non-iterative rate control
genericity
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
JPEG
MPEG-4 VTC
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Coding rate-distortion
comparisons
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PSNR (dB)
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0
0.5
1
1.5
2
bpp
J2K R
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J2K NR
JPEG
ITU-T VICA Workshop
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VTC
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Lossless coding performance
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10.00
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compression ratio
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bike
café
cmpnd1
JPEG2000
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chart
aerial2
JPEG-LS
target
L-JPEG
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
us
average
PNG
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JPEG 2000 algorithm overview
ITU-T
code-block
sign
MSB
Quantization
Wavelet
Transform
LSB
MSB
Entropy
Coding
LSB
Bit stream
Original image
MSB
LSB
Bit stream code-block 1
MSB
LSB
Bit stream code-block 2
MSB
LSB
Packet 1
Packet 2
Packet P
Bit stream code-block 3
header
MSB
LSB
Bit stream code-block N-1
MSB
Rate
Allocation
codestream
LSB
Bit stream code-block N
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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JPEG 2000 algorithm overview
ITU-T Progressive by resolution
Progressive by quality
MSB
LSB
Res 0
MSB
LSB
Res 1
MSB
LSB
LSB
MSB
Res 2
LSB
MSB
Layer 1
header
Layer 3
header
codestream
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Layer 2
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
codestream
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Layer (SNR) progressive example
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22-23 July 2005, ITU Headquarter, Geneva
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Layer (SNR) progressive example
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Layer (SNR) progressive example
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22-23 July 2005, ITU Headquarter, Geneva
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Resolution progressive example
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Resolution progressive example
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Resolution progressive example
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22-23 July 2005, ITU Headquarter, Geneva
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Resolution progressive example
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Compression example
JPEG at 0.25 bpp (detail)
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22-23 July 2005, ITU Headquarter, Geneva
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Compression example
JPEG2000 at 0.25 bpp (detail)
ITU-T
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22-23 July 2005, ITU Headquarter, Geneva
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Compression example
Comparison between Jpeg/Jpeg 2000
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Jpeg 20:1
Jpeg 50:1
Jp2 20:1
Jp2 50:1
Original Image
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
Jp2 100:1
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Region of Interest coding
principle
o Region of Interest (ROI) coding allows a non-uniform
ITU-T
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distribution of quality. The ROI is coded with a higher
quality than the background (BG). A higher compression
ratio can be achieved with same or higher quality inside
ROIs.
o Static ROIs are defined at encoding time and are
suitable for storage, fixed transmission, remote sensing,
etc. Commonly referred to as ROI coding.
o Dynamic ROIs are defined interactively by a user in a
client/server situation during a progressive transmission.
Suitable for telemedicine, PDAs, mobile
communications, etc. They can be achieved by the
dynamic generation of layers matching the user’s
request.
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Lossless ROI mask generation
ROI in image domain
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Final ROI mask
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ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Encoding ROIs: scaling
Original
ITU-T
MSB
General scaling
Maxshift
ROI
s’
s
LSB
o Shift up quantized ROI coefficients by s bitplanes. The
value of s is recorded in the codestream header for each
ROI.
o At decoder ROI coefficients are unshifted prior to
dequantization.
o The ROI mask is required at both, encoder and decoder.
o In maxshift, s is large enough to separate ROI and BG
• No ROI mask required at decoder
• ROI <-> BG quality differential not controlled
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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ROI Maxshift example
ITU-T
ROI
256:1
45:1 (almost all ROI decoded)
No ROI
ROI covers 5% of image, 2 lowest resolution levels in ROI mask. Magnified portion shown.
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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ROI Maxshift example (cont’d)
ITU-T
ROI
16:1
4:1 (complete decode)
No ROI
ROI covers 5% of image, 2 lowest resolution levels in ROI mask. Magnified portion shown.
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Error resilience example
ITU-T
16:1 compression ratio. Transmission error rate 10-5. No errors in codestream header.
Magnified portion shown.
No transmission errors
No error resilience
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Full error resilience
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Error protection techniques
ITU-T
o Coded image data
• Code-block partition
• Regular termination of arithmetic coder
• Segmentation symbols
o Packet heads
• Start of packet markers
• Packet heads in main / tile codestream
header
• Partition of packets into precincts
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Error resilience visual results
Bit error rate = 10-5
ITU-T
JPEG 16:1 CR
JPEG 2000 16:1 CR
Images with median quality, of 200 runs
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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Error resilience visual results
Bit error rate = 10-4
ITU-T
JPEG 16:1 CR
JPEG 2000 16:1 CR
Images with median quality, of 200 runs
dates
ITU-T VICA Workshop
22-23 July 2005, ITU Headquarter, Geneva
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JPEG 2000 File Format: JP2
ITU-T
o JP2 is the optional JPEG 2000 file format
to encapsulate JPEG 2000 codestreams.
• Extension: jp2
• Allows to embed XML information (e.g.,
metadata)
• Alpha channel (e.g., transparency)
• Accurate color interpretation
• “True color” and “palette color” supported
• Intellectual property information
• Capture and default display resolution
• File “magic number”
• File transfer errors (ASCII ftp, 7 bit e-mail,
etc.)
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