Publications - Xavier Delaunay
Abstract : This paper proposes a complete compression and coding scheme for on-board
satellite applications considering the main on-board constraints:
low computational power and easy bit-rate control. The proposed coding
scheme improves the performance of the current CCSDS recommendation
(Consultative Committee for Space Data Systems) for a low additional
complexity. We consider post-transforms in the wavelet domain, select
the best representation for each block of wavelet coefficients, and
encode it into an embedded bit stream. After applying a classical
wavelet transform of the image, several concurrent representations
of blocks of wavelet coefficients are generated. The best representations
are then selected according to a rate-distortion criterion. Finally,
a specific bit-plane encoder derived from the CCSDS recommendation
produces an embedded bit stream ensuring the easy rate control required.
In this article, both the post-transforms and the best representation
selection have been adapted to the low complexity constraint and
the CCSDS coder has been modified to compress post-transformed representations.
BibTeX :
@article {springerlink:10.1007/s12243-011-0252-0,
author = {Delaunay, Xavier and Chabert, Marie and Charvillat, Vincent and Morin, Géraldine},
affiliation = {NOVELTIS, Parc technologique du canal, 2 av. de l’Europe, 31520 Ramonville-Saint-Agne, France},
title = {Satellite image compression by concurrent representations of wavelet blocks},
journal = {Annals of Telecommunications},
publisher = {Springer Paris},
issn = {0003-4347},
keyword = {Engineering},
pages = {71-80},
volume = {67},
issue = {1},
url = {http://dx.doi.org/10.1007/s12243-011-0252-0},
note = {10.1007/s12243-011-0252-0},
year = {2012}
}
Copyright © 2011, Institut Télécom and Springer-Verlag.
Abstract :
This paper proposes a selective compression scheme to enhance the
quality of regions of interest and to avoid wasting coding resources on
irrelevant parts of satellite images. Although 80\% of SPOT 5 images
contain clouds, the information about clouds is irrelevant since the
main mission of this satellite, like many other optical Earth
observation satellite, is Earth ground observation. However in current
on-board compression algorithms pixels of clouds are processed as any
other pixels of the image and are transmitted with the same quality and
bit-rate. This results in a waste of data rate which could have been
used either to enhance the quality of the relevant part of the
transmitted image (thanks to progressive coding) or to transmit more
images. The goal of selective image coding is to avoid this waste by
on-board cloud detection [1] and region of interest (ROI) coding
techniques. This paper focuses on this second point: the implementation
of ROI coding techniques in an algorithm derived of the CCSDS 122
recommendation [2].
Two ROI coding methods have been integrated to the algorithm: the
maxshift and the scaling methods. Both respect the constraint of
progressive coding and fine region delineation. Both also allow multiple
levels of interest, that is, several ROI with different levels of
interest and a background region. After the wavelet transform, the
maxshift method operates by up-shifting all the ROI bitplanes above the
most significant bitplane of the background region. Scaling operates by
multiplying the ROI wavelet coefficients by a scaling factor or by
up-shifting the ROI bitplanes by an number of shifts equivalent to this
scaling factor, not necessarily greater the most significant
bitplane. As the coding process stops before it reaches the least
significant bitplane, up-shifted ROI wavelet coefficients are coded with
greater accuracy than the background coefficients. As a result, ROI are
transmitted with better quality than the background region.
First, we shall motivate the choice of the maxshift and scaling methods.
Then, both methods will be detailed. The implemented algorithm does not
comply with the CCSDS 122 recommendation. Thus, in the next section, the
modifications required to add ROI coding features to the algorithm will
be developed. Finally, the proposed scheme will be evaluated by
comparing rate-distortion curves obtained by the compression of several
Quickbird images with the ROI methods and the original CCSDS 122 coder.
[1] C. Thiebaut, P. Dejean, P. Fillatreau, A. Speciel and C. Latry,
"On-Board Cloud Detection for Selective Compression of High-Resolution
Images," On-Board Payload Data Compression Workshop, OBPDC 2008.
[2] P-S. Yeh et al., "The New CCSDS Image Compression Recommendation,"
in proc. of the IEEE Aerospace Conference, pp. 1–8, Big Sky, MT, March
5–12, 2005.
BibTeX :
@inproceedings{delaunay:obpdc10,
author = {Xavier Delaunay and Carole Thiebaut and Marie Chabert and Vincent
Charvillat and Géraldine Morin},
title = {Progressive Coding of Satellite Images with Regions of Interest},
booktitle = {On-Board Payload Data Compression Workshop},
year = {2010},
address = {Toulouse, France},
month = oct,
url = {http://www.congrex.nl/10c19/}
}
Abstract : This paper proposes a novel
compression scheme with a tunable complexity-rate-distortion
trade-off. As images increase in size and resolution, more
efficient compression schemes with low complexity are required
on-board Earth observation satellites. The standard of the
Consultative Committee for Space Data Systems (CCSDS) defines a
strip-based compression scheme with the advantages of a low
complexity and an easy rate control [CCSDS, Image Data
Compression Recommended Standard CCSDS 122.0-B-1 Blue Book,
November 2005]. However, future mission specifications expect
higher performance in terms of rate-distortion. The scheme
proposed in this paper intends to perform better than the CCSDS
standard while preserving low complexity and easy rate control.
Moreover, to comply with existing on-board devices, the
proposed core compression engine still uses the wavelet
transform but in association with a linear post-processing
inspired from the bandelet transform. The post-transform
decomposes a small block of wavelet coefficients on a
particular basis. This basis is adaptively selected within a
predefined dictionary by rate-distortion optimization. The
computational complexity depends upon the dictionary size and
of the basis structure. An extremely simple dictionary, reduced
to the Hadamard basis, is proposed. The post-transform
efficiency is illustrated by experiments on various Earth
observation images provided by the French Space Agency (CNES).
BibTeX :
@article{delaunay:sigpro09,
author = {Xavier Delaunay and Marie Chabert and Vincent Charvillat and Géraldine Morin},
title = {Satellite Image Compression by Post-Transforms in the Wavelet Domain},
journal = {Elsevier Signal Processing},
year = {2010},
volume = {90},
number = {2},
pages = {599--610},
doi = {http://dx.doi.org/10.1016/j.sigpro.2009.07.024}
}
Copyright © 2009 Elsevier B.V. All rights reserved.
Abstract : Les post-transformées permettent
d’exploiter des dépendances linéaires entre coefficients
d’ondelettes voisins. Dans ce papier, le schéma de compression
par posttransformée est modifié afin d’être adapté à une
compression progressive. De plus, prenant en considération les
contraintes d’un algorithme de compression à bord d’un
satellite, la complexité calculatoire de cette méthode est
réduite au minimum. Le codeur par plans de bits du CCSDS est
ensuite modifié afin de pouvoir coder la posttransformée.
Ainsi, les avantages de la post-transformée et du codeur du
CCSDS sont combinés. Cela permet d’améliorer les résultats en
compression.
BibTeX :
@inproceedings{delaunay:coresa09,
author = {Xavier Delaunay and Carole Thiebaut and Marie Chabert and Géraldine Morin},
title = {Codage progressif de post-transformées par le codeur du {CCSDS}},
booktitle = {CORESA'09},
publisher = {France Telecom R\&D},
year = {2009},
url = {http://coresa2009.enseeiht.fr/}
}
-
X. Delaunay, M. Chabert, V. Charvillat, G. Morin and R.
Ruiloba, "Satellite image compression by directional
decorrelation of wavelet coefficients", In
ICASSP'08, pp. 1193-1196, IEEE, Las Vegas,
NV, April 2008.
doi:10.1109/ICASSP.2008.4517829
[Abstract]
[BibTeX]
[Copyright]
Abstract : This paper deals with satellite
image compression based on a post-processing of the wavelet
transform of images. The bandelet transform is a directional
post-processing of wavelet coefficients. Thanks to a low
computational complexity, this transform is a good candidate
for future on-board satellite image compression systems. This
paper first analyzes the ability of the bandelets to exploit
directional correlations between wavelet coefficients. This
study leads to an improved post-processing with a better
decorrelation of adjacent wavelet coefficients in the vertical
or in the horizontal direction taking into account the wavelet
subband orientations. To perform even better decorrelation,
bases are also learned by PCA. This results in an improved
compression performance without increasing the computational
complexity.
BibTeX :
@inproceedings{delaunay:icassp08,
author = {Xavier Delaunay and Marie Chabert and Vincent Charvillat and Géraldine Morin and Rosario Ruiloba},
title = {Satellite image compression by directional decorrelation of wavelet coefficients},
booktitle = {ICASSP'08},
publisher = {IEEE},
year = {2008},
pages = {1193--1196},
doi = {http://dx.doi.org/10.1109/ICASSP.2008.4517829}
}
Copyright 2008 IEEE. Published in the IEEE 2008 International
Conference on Acoustics, Speech, and Signal Processing (ICASSP
2008), scheduled for March 30 - April 4, 2008 in Las Vegas,
Nevada, U.S.A. Personal use of this material is permitted.
However, permission to reprint/republish this material for
advertising or promotional purposes or for creating new
collective works for resale or redistribution to servers or
lists, or to reuse any copyrighted component of this work in
other works, must be obtained from the IEEE. Contact: Manager,
Copyrights and Permissions / IEEE Service Center / 445 Hoes
Lane / P.O. Box 1331 / Piscataway, NJ 08855-1331, USA.
Telephone: + Intl. 908-562-3966.
-
X. Delaunay, C. Thiebaut, E. Christophe, R. Ruiloba, M.
Chabert, V. Charvillat and G. Morin, "Lossy compression by post-transforms in the
wavelet domain", In On-Board Payload Data
Compression Workshop, Noordwijk, The Netherlands, June
2008.
http://www.congrex.nl/08c20/
[Abstract]
[BibTeX]
Abstract : Current state-of-the-art on-board
image compression systems are based on the wavelet transform.
However, redundancies can still be found between the wavelet
coefficients. To exploit these remaining redundancies and
increase the compression efficiency, the new post-transform
compression scheme applies a second transform on blocks of
coefficients. This paper proposes to adapt the post-transform
process to on-board constraints using the low complexity
Hadamard post-transform and describes how it can be efficiently
included in the bit-plane encoder of the CCSDS (Consultative
Committee for Space Data Systems) recommendation. Compression
performance is provided for each adjustment made to the
post-transform process.
BibTeX :
@inproceedings{delaunay:obpdc08,
author = {Xavier Delaunay and Carole Thiebaut and Emmanuel Christophe and Rosario Ruiloba and Marie Chabert and Vincent Charvillat and Géraldine Morin},
title = {Lossy compression by post-transforms in the wavelet domain},
booktitle = {On-Board Payload Data Compression Workshop},
year = {2008},
url = {http://www.congrex.nl/08c20/}
}
-
C. Thiebaut, X. Delaunay, C. Latry and G. Moury, "CNES studies
for on-board compression of high-resolution satellite images",
In Satellite Data Compression, Communication, and
Processing IV, pp. 70840F.1-70840F.8, SPIE, San
Diego, CA, USA, August 2008.
doi:10.1117/12.798121
[Abstract]
[BibTeX]
Abstract : Future high resolution instruments
planned by CNES for space remote sensing missions will lead to
higher bit rates because of the increase in resolution and
dynamic range. For example, the ground resolution improvement
induces a data rate multi-plied by 8 from SPOT4 to SPOT5 and by
28 to PLEIADES-HR. Lossy data compression with low complexity
algorithms is then needed since compression ratio are always
higher. New image compression algorithms have been used to
increase their compression performance while complying with
image quality requirements from the community of users and
experts. Thus, DPCM algorithm used on-board SPOT4 was replaced
by a DCT-based compressor on-board SPOT5. Recent compression
algorithms such as PLEIADES-HR one use a wavelet-transform and
a bit-plane encoder. But future compressors will have to be
more powerful to reach higher compression ratios. New
transforms are studied by CNES to exceed the DWT but a
per-formance gap could be obtained with selective compression.
This article gives an overview of CNES past and present studies
of on-board compression algorithms for high-resolution images.
BibTeX :
@inproceedings{thiebaut:spie08,
author = {Carole Thiebaut and Xavier Delaunay and Christophe Latry and Gilles Moury},
title = {{CNES} studies for on-board compression of high-resolution satellite images},
booktitle = {Satellite Data Compression, Communication, and Processing IV},
publisher = {SPIE},
year = {2008},
pages = {70840F.1--70840F.8},
doi = {http://dx.doi.org/10.1117/12.798121}
}
-
X. Delaunay, E. Christophe, C. Thiebaut and V. Charvillat,
"Best post-transforms selection in a rate
distortion sense", In ICIP'08, pp. 2896-2899,
IEEE, San Diego, CA, USA, October 2008.
doi:10.1109/ICIP.2008.4712400
[Abstract]
[BibTeX]
[Copyright]
Abstract : This paper deals with the
optimization of a new technique of image compression. After the
wavelet transform of an image, blocks of coefficients are
further linearly decomposed using a basis selected in a
dictionary. This dictionary is known by both the encoder and
the decoder. This approach is a generalization of the bandelet
transform. This paper investigates the problem of the best
basis selection. On each block of wavelet coefficients, this
selection is made by minimization of a Lagrangian
rate-distortion criterion. Theoretical expressions of the
optimal Lagrangian multiplier can be computed based on
asymptotic hypotheses. A nearly exhaustive search of the
optimal Lagrangian multiplier is done for the compression of
high resolution satellite images. This numerical study
validates the asymptotic theoretical expressions but as well
provides a refined expression of the Lagrangian multiplier. At
last, the compression results obtained using those different
expressions are compared to the optimal compression results
obtained with the exhaustive search.
BibTeX :
@inproceedings{delaunay:icip08,
author = {Xavier Delaunay and Emmanuel Christophe and Carole Thiebaut and Vincent Charvillat},
title = {Best post-transforms selection in a rate distortion sense},
booktitle = {ICIP'08},
publisher = {IEEE},
year = {2008},
pages = {2896--2899},
doi = {http://dx.doi.org/10.1109/ICIP.2008.4712400}
}
Copyright 2008 IEEE. Published in the IEEE 2008 International
Conference on Image Processing (ICIP 2008), scheduled for
October 12-15, 2008 in San Diego, California, U.S.A. Personal
use of this material is permitted. However, permission to
reprint/republish this material for advertising or promotional
purposes or for creating new collective works for resale or
redistribution to servers or lists, or to reuse any copyrighted
component of this work in other works, must be obtained from
the IEEE. Contact: Manager, Copyrights and Permissions / IEEE
Service Center / 445 Hoes Lane / P.O. Box 1331 / Piscataway, NJ
08855-1331, USA. Telephone: + Intl. 908-562-3966.
Abstract : Le CNES s'intéresse aux nouvelles
transformées pour accroître les performances de la compression
d'images à bord des satellites d'observation de la Terre. Dans
cette thèse nous étudions les post-transformées. Elles sont
appliquées après la transformée en ondelettes. Chaque bloc de
coefficients d'ondelettes est de nouveau transformé dans une
base sélectionnée dans un dictionnaire par minimisation d'un
critère débit-distorsion. Nous commençons par mettre en
évidence des dépendances entre coefficients d'ondelettes qui
limitent les performances en compression. Nous étudions ensuite
la transformée en bandelettes par blocs, qui est à l'origine
des post-transformées, et nous en optimisons les paramètres
pour la compression d'images satellite. En particulier nous
adaptons la méthode d'optimisation de Shoham et Gersho à la
sélection de la meilleure base de bandelettes. Nous en
déduisons une formule du multiplicateur de Lagrange optimal qui
intervient dans le critère de sélection. Dans un deuxième
temps, nous analysons les dépendances entre coefficients
d'ondelettes qui ne sont pas prises en comptes par les
bandelettes et nous définissons de nouvelles bases de
post-transformées. Les bases construites par ACP minimisent les
corrélations entre coefficients post-transformés et compactent
l'énergie de chaque bloc sur un petit nombre de coefficients.
Cette propriété est exploitée lors du codage entropique. Enfin,
nous modifions le critère de sélection des bases pour adapter
la post-transformée à une compression progressive. Nous
employons alors la post-transformée de Hadamard dans le codeur
du CCSDS le tout ayant une faible complexité calculatoire.
BibTeX :
@phdthesis{delaunay:thesis08,
author = {Xavier Delaunay},
title = {Compression d'images satellite par post-transformées dans le domaine ondelettes},
school = {Institut National Polytechnique de Toulouse},
year = {2008},
url = {http://ethesis.inp-toulouse.fr/archive/00000693/}
}
Abstract : This paper studies the performance
of the ZC contexts in JPEG2000. A quality criterion based on
the mutual information is introduced. According to this
criterion, there exist ZC contexts which are not effective in
any bit-plane. They can thus be merged with others without
significant loss of the compression efficiency. Since the
contextual conditional probabilities strongly depend on the
bit-planes, an adaptation of the contexts to the bit-planes is
also proposed. First, an optimal context quantizer is used on
each bit-planes, then a simple greedy entropy minimization
procedure allows to combine the ZC contexts in JPEG2000. The
results are compared with a global combination of JPEG2000 ZC
contexts. Tests have been performed on a real satellite image
data base. With only four ZC contexts, the PSNR is less than
0.01 dB lower than the PSNR with the nine ZC contexts.
BibTeX :
@inproceedings{delaunay:icassp07,
author = {Xavier Delaunay and Marie Chabert and Géraldine Morin and Vincent Charvillat},
title = {Bit-plane analysis and contexts combining of {JPEG2000} contexts for on-board satellite image compression},
booktitle = {ICASSP'07},
publisher = {IEEE},
year = {2007},
pages = {1057--1060},
doi = {http://dx.doi.org/10.1109/ICASSP.2007.366093}
}
Copyright 2007 IEEE. Published in the IEEE 2007 International
Conference on Acoustics, Speech, and Signal Processing (ICASSP
2007), scheduled for April 16-20, 2007 in Honolulu, Hawaii.
Personal use of this material is permitted. However, permission
to reprint/republish this material for advertising or
promotional purposes or for creating new collective works for
resale or redistribution to servers or lists, or to reuse any
copyrighted component of this work in other works, must be
obtained from the IEEE. Contact: Manager, Copyrights and
Permissions / IEEE Service Center / 445 Hoes Lane / P.O. Box
1331 / Piscataway, NJ 08855-1331, USA. Telephone: + Intl.
908-562-3966.
Abstract : Cet article s’intéresse à la
compression d’images satellite. La technique proposée met en
oeuvre la transformée en ondelettes couplée à une
post-transformée par blocs sélectionnée dans un dictionnaire de
bases. L’originalité du travail réside dans le dictionnaire
utilisé. Ce dictionnaire est constitué de bases construites à
partir de l’Analyse en Composantes Principales (ACP) sur une
base d’apprentissage de blocs de coefficients d’ondelettes. La
post-transformée proposée permet d’éliminer les corrélations
entre coefficients d’ondelettes voisins. Elle bénéficie aussi
de la propriété de concentration d’énergie de l’ACP qui est
exploitée au moment du codage.
BibTeX :
@inproceedings{delaunay:gretsi07,
author = {Xavier Delaunay and Marie Chabert and Géraldine Morin and Carole Thiebaut},
title = {Post-transformée dans le domaine ondelettes appliquée à la compression d'images satellite},
booktitle = {GRETSI'07},
publisher = {CNRS},
year = {2007},
pages = {1185--1188},
url = {http://hdl.handle.net/2042/17721}
}
Abstract : La résolution des images acquises à
bord des satellites d’observation de la terre est de plus en
plus grande et la compression à bord doit donc être de plus en
plus performante pour transmettre les données au sol.
L’augmentation des capacités de calcul et de mémoire permet la
mise en place d’algorithmes de plus en plus complexes.
Actuellement, on envisage des compresseurs capables de
compenser les faiblesses de la transformée en ondelettes
séparable, et qui utiliseraient une autre transformée et/ou des
codeurs plus performants. Dans cette communication, nous
mettons en évidence deux sortes de corrélations résiduelles
entre coefficients d’ondelettes qu’il serait souhaitable
d’éliminer pour améliorer la compression. Les premières
corrélations sont situées dans un voisinage local. Les secondes
sont liées aux structures géométriques de l’image et sont
observées sur de plus grandes distances.
BibTeX :
@inproceedings{delaunay:coresa06,
author = {Xavier Delaunay and Carole Thiebaut and Vincent Charvillat},
title = {Compression embarquée d'images satellites : vers l'exploitation de la géométrie},
booktitle = {CORESA'06},
publisher = {France Telecom R\&D},
year = {2006},
pages = {12--17},
url = {http://www.stlo.unicaen.fr/coresa2006/}
}