162 research outputs found
SCALABLE AUDIO CODING USING WATERMARKING
A scalable audio coding method is proposed using a technique, Quantization Index Modulation, borrowed from watermarking. Some of the information of each layer output is embedded (watermarked) in the previous layer. This approach leads to a saving in bitrate while keeping the distortion almost unchanged. This makes the scalable coding system more efficient in terms of Rate-Distortion. The results show that the proposed method outperforms the scalable audio coding based on reconstruction error quantization which is used in practical systems such as MPEG-4 AAC
Preserving data integrity of encoded medical images: the LAR compression framework
International audienceThrough the development of medical imaging systems and their integration into a complete information system, the need for advanced joint coding and network services becomes predominant. PACS (Picture Archiving and Communication System) aims to acquire, store and compress, retrieve, present and distribute medical images. These systems have to be accessible via the Internet or wireless channels. Thus protection processes against transmission errors have to be added to get a powerful joint source-channel coding tool. Moreover, these sensitive data require confidentiality and privacy for both archiving and transmission purposes, leading to use cryptography and data embedding solutions. This chapter introduces data integrity protection and developed dedicated tools of content protection and secure bitstream transmission for medical encoded image purposes. In particular, the LAR image coding method is defined together with advanced securization services
Audio Coding Based on Integer Transforms
Die Audiocodierung hat sich in den letzten Jahren zu einem sehr
populÀren Forschungs- und Anwendungsgebiet entwickelt. Insbesondere
gehörangepasste Verfahren zur Audiocodierung, wie etwa MPEG-1 Layer-3
(MP3) oder MPEG-2 Advanced Audio Coding (AAC), werden hÀufig zur
effizienten Speicherung und Ăbertragung von Audiosignalen verwendet. FĂŒr
professionelle Anwendungen, wie etwa die Archivierung und Ăbertragung im
Studiobereich, ist hingegen eher eine verlustlose Audiocodierung angebracht.
Die bisherigen AnsĂ€tze fĂŒr gehörangepasste und verlustlose
Audiocodierung sind technisch völlig verschieden. Moderne
gehörangepasste Audiocoder basieren meist auf FilterbÀnken, wie etwa der
ĂŒberlappenden orthogonalen Transformation "Modifizierte Diskrete
Cosinus-Transformation" (MDCT). Verlustlose Audiocoder hingegen
verwenden meist prÀdiktive Codierung zur Redundanzreduktion. Nur wenige
AnsÀtze zur transformationsbasierten verlustlosen Audiocodierung wurden
bisher versucht.
Diese Arbeit prÀsentiert einen neuen Ansatz hierzu, der das
Lifting-Schema auf die in der gehörangepassten Audiocodierung
verwendeten ĂŒberlappenden Transformationen anwendet. Dies ermöglicht
eine invertierbare Integer-Approximation der ursprĂŒnglichen
Transformation, z.B. die IntMDCT als Integer-Approximation der MDCT. Die
selbe Technik kann auch fĂŒr FilterbĂ€nke mit niedriger Systemverzögerung
angewandt werden. Weiterhin ermöglichen ein neuer, mehrdimensionaler
Lifting-Ansatz und eine Technik zur Spektralformung von
Quantisierungsfehlern eine Verbesserung der Approximation der
ursprĂŒnglichen Transformation.
Basierend auf diesen neuen Integer-Transformationen werden in dieser
Arbeit neue Verfahren zur Audiocodierung vorgestellt. Die Verfahren
umfassen verlustlose Audiocodierung, eine skalierbare verlustlose
Erweiterung eines gehörangepassten Audiocoders und einen integrierten
Ansatz zur fein skalierbaren gehörangepassten und verlustlosen
Audiocodierung. SchlieĂlich wird mit Hilfe der Integer-Transformationen
ein neuer Ansatz zur unhörbaren Einbettung von Daten mit hohen
Datenraten in unkomprimierte Audiosignale vorgestellt.In recent years audio coding has become a very popular field for
research and applications. Especially perceptual audio coding schemes,
such as MPEG-1 Layer-3 (MP3) and MPEG-2 Advanced Audio Coding (AAC), are
widely used for efficient storage and transmission of music
signals. Nevertheless, for professional applications, such as archiving
and transmission in studio environments, lossless audio coding schemes
are considered more appropriate.
Traditionally, the technical approaches used in perceptual and lossless
audio coding have been separate worlds. In perceptual audio coding, the
use of filter banks, such as the lapped orthogonal transform "Modified
Discrete Cosine Transform" (MDCT), has been the approach of choice being
used by many state of the art coding schemes. On the other hand,
lossless audio coding schemes mostly employ predictive coding of
waveforms to remove redundancy. Only few attempts have been made so far
to use transform coding for the purpose of lossless audio coding.
This work presents a new approach of applying the lifting scheme to
lapped transforms used in perceptual audio coding. This allows for an
invertible integer-to-integer approximation of the original transform,
e.g. the IntMDCT as an integer approximation of the MDCT. The same
technique can also be applied to low-delay filter banks. A generalized,
multi-dimensional lifting approach and a noise-shaping technique are
introduced, allowing to further optimize the accuracy of the
approximation to the original transform.
Based on these new integer transforms, this work presents new audio
coding schemes and applications. The audio coding applications cover
lossless audio coding, scalable lossless enhancement of a perceptual
audio coder and fine-grain scalable perceptual and lossless audio
coding. Finally an approach to data hiding with high data rates in
uncompressed audio signals based on integer transforms is described
Audio Coding Based on Integer Transforms
Die Audiocodierung hat sich in den letzten Jahren zu einem sehr
populÀren Forschungs- und Anwendungsgebiet entwickelt. Insbesondere
gehörangepasste Verfahren zur Audiocodierung, wie etwa MPEG-1 Layer-3
(MP3) oder MPEG-2 Advanced Audio Coding (AAC), werden hÀufig zur
effizienten Speicherung und Ăbertragung von Audiosignalen verwendet. FĂŒr
professionelle Anwendungen, wie etwa die Archivierung und Ăbertragung im
Studiobereich, ist hingegen eher eine verlustlose Audiocodierung angebracht.
Die bisherigen AnsĂ€tze fĂŒr gehörangepasste und verlustlose
Audiocodierung sind technisch völlig verschieden. Moderne
gehörangepasste Audiocoder basieren meist auf FilterbÀnken, wie etwa der
ĂŒberlappenden orthogonalen Transformation "Modifizierte Diskrete
Cosinus-Transformation" (MDCT). Verlustlose Audiocoder hingegen
verwenden meist prÀdiktive Codierung zur Redundanzreduktion. Nur wenige
AnsÀtze zur transformationsbasierten verlustlosen Audiocodierung wurden
bisher versucht.
Diese Arbeit prÀsentiert einen neuen Ansatz hierzu, der das
Lifting-Schema auf die in der gehörangepassten Audiocodierung
verwendeten ĂŒberlappenden Transformationen anwendet. Dies ermöglicht
eine invertierbare Integer-Approximation der ursprĂŒnglichen
Transformation, z.B. die IntMDCT als Integer-Approximation der MDCT. Die
selbe Technik kann auch fĂŒr FilterbĂ€nke mit niedriger Systemverzögerung
angewandt werden. Weiterhin ermöglichen ein neuer, mehrdimensionaler
Lifting-Ansatz und eine Technik zur Spektralformung von
Quantisierungsfehlern eine Verbesserung der Approximation der
ursprĂŒnglichen Transformation.
Basierend auf diesen neuen Integer-Transformationen werden in dieser
Arbeit neue Verfahren zur Audiocodierung vorgestellt. Die Verfahren
umfassen verlustlose Audiocodierung, eine skalierbare verlustlose
Erweiterung eines gehörangepassten Audiocoders und einen integrierten
Ansatz zur fein skalierbaren gehörangepassten und verlustlosen
Audiocodierung. SchlieĂlich wird mit Hilfe der Integer-Transformationen
ein neuer Ansatz zur unhörbaren Einbettung von Daten mit hohen
Datenraten in unkomprimierte Audiosignale vorgestellt.In recent years audio coding has become a very popular field for
research and applications. Especially perceptual audio coding schemes,
such as MPEG-1 Layer-3 (MP3) and MPEG-2 Advanced Audio Coding (AAC), are
widely used for efficient storage and transmission of music
signals. Nevertheless, for professional applications, such as archiving
and transmission in studio environments, lossless audio coding schemes
are considered more appropriate.
Traditionally, the technical approaches used in perceptual and lossless
audio coding have been separate worlds. In perceptual audio coding, the
use of filter banks, such as the lapped orthogonal transform "Modified
Discrete Cosine Transform" (MDCT), has been the approach of choice being
used by many state of the art coding schemes. On the other hand,
lossless audio coding schemes mostly employ predictive coding of
waveforms to remove redundancy. Only few attempts have been made so far
to use transform coding for the purpose of lossless audio coding.
This work presents a new approach of applying the lifting scheme to
lapped transforms used in perceptual audio coding. This allows for an
invertible integer-to-integer approximation of the original transform,
e.g. the IntMDCT as an integer approximation of the MDCT. The same
technique can also be applied to low-delay filter banks. A generalized,
multi-dimensional lifting approach and a noise-shaping technique are
introduced, allowing to further optimize the accuracy of the
approximation to the original transform.
Based on these new integer transforms, this work presents new audio
coding schemes and applications. The audio coding applications cover
lossless audio coding, scalable lossless enhancement of a perceptual
audio coder and fine-grain scalable perceptual and lossless audio
coding. Finally an approach to data hiding with high data rates in
uncompressed audio signals based on integer transforms is described
WG1N5315 - Response to Call for AIC evaluation methodologies and compression technologies for medical images: LAR Codec
This document presents the LAR image codec as a response to Call for AIC evaluation methodologies and compression technologies for medical images.This document describes the IETR response to the specific call for contributions of medical imaging technologies to be considered for AIC. The philosophy behind our coder is not to outperform JPEG2000 in compression; our goal is to propose an open source, royalty free, alternative image coder with integrated services. While keeping the compression performances in the same range as JPEG2000 but with lower complexity, our coder also provides services such as scalability, cryptography, data hiding, lossy to lossless compression, region of interest, free region representation and coding
A NOVEL JOINT PERCEPTUAL ENCRYPTION AND WATERMARKING SCHEME (JPEW) WITHIN JPEG FRAMEWORK
Due to the rapid growth in internet and multimedia technologies, many new
commercial applications like video on demand (VOD), pay-per-view and real-time
multimedia broadcast etc, have emerged. To ensure the integrity and confidentiality of
the multimedia content, the content is usually watermarked and then encrypted or vice
versa. If the multimedia content needs to be watermarked and encrypted at the same
time, the watermarking function needs to be performed first followed by encryption
function. Hence, if the watermark needs to be extracted then the multimedia data
needs to be decrypted first followed by extraction of the watermark. This results in
large computational overhead. The solution provided in the literature for this problem
is by using what is called partial encryption, in which media data are partitioned into
two parts - one to be watermarked and the other is encrypted. In addition, some
multimedia applications i.e. video on demand (VOD), Pay-TV, pay-per-view etc,
allow multimedia content preview which involves âperceptualâ encryption wherein all
or some selected part of the content is, perceptually speaking, distorted with an
encryption key. Up till now no joint perceptual encryption and watermarking scheme
has been proposed in the literature.
In this thesis, a novel Joint Perceptual Encryption and Watermarking (JPEW)
scheme is proposed that is integrated within JPEG standard. The design of JPEW
involves the design and development of both perceptual encryption and watermarking
schemes that are integrated in JPEG and feasible within the âpartialâ encryption
framework. The perceptual encryption scheme exploits the energy distribution of AC
components and DC components bitplanes of continuous-tone images and is carried
out by selectively encrypting these AC coefficients and DC components bitplanes.
The encryption itself is based on a chaos-based permutation reported in an earlier
work. Similarly, in contrast to the traditional watermarking schemes, the proposed
watermarking scheme makes use of DC component of the image and it is carried out
by selectively substituting certain bitplanes of DC components with watermark bits.
vi ii
Apart from the aforesaid JPEW, additional perceptual encryption scheme, integrated
in JPEG, has also been proposed. The scheme is outside of joint framework and
implements perceptual encryption on region of interest (ROI) by scrambling the DCT
blocks of the chosen ROI.
The performances of both, perceptual encryption and watermarking schemes are
evaluated and compared with Quantization Index modulation (QIM) based
watermarking scheme and reversible Histogram Spreading (RHS) based perceptual
encryption scheme. The results show that the proposed watermarking scheme is
imperceptible and robust, and suitable for authentication. Similarly, the proposed
perceptual encryption scheme outperforms the RHS based scheme in terms of number
of operations required to achieve a given level of perceptual encryption and provides
control over the amount of perceptual encryption. The overall security of the JPEW
has also been evaluated. Additionally, the performance of proposed separate
perceptual encryption scheme has been thoroughly evaluated in terms of security and
compression efficiency. The scheme is found to be simpler in implementation, have
insignificant effect on compression ratios and provide more options for the selection
of control factor
Fast watermarking of MPEG-1/2 streams using compressed-domain perceptual embedding and a generalized correlator detector
A novel technique is proposed for watermarking of MPEG-1 and MPEG-2 compressed video streams. The proposed scheme is applied directly in the domain of MPEG-1 system streams and MPEG-2 program streams (multiplexed streams). Perceptual models are used during the embedding process in order to avoid degradation of the video quality. The watermark is detected without the use of the original video sequence. A modified correlation-based detector is introduced that applies nonlinear preprocessing before correlation. Experimental evaluation demonstrates that the proposed scheme is able to withstand several common attacks. The resulting watermarking system is very fast and therefore suitable for copyright protection of compressed video
WAVELET BASED DATA HIDING OF DEM IN THE CONTEXT OF REALTIME 3D VISUALIZATION (Visualisation 3D Temps-Réel à Distance de MNT par Insertion de Données Cachées Basée Ondelettes)
The use of aerial photographs, satellite images, scanned maps and digital elevation models necessitates the setting up of strategies for the storage and visualization of these data. In order to obtain a three dimensional visualization it is necessary to drape the images, called textures, onto the terrain geometry, called Digital Elevation Model (DEM). Practically, all these information are stored in three different files: DEM, texture and position/projection of the data in a geo-referential system. In this paper we propose to stock all these information in a single file for the purpose of synchronization. For this we have developed a wavelet-based embedding method for hiding the data in a colored image. The texture images containing hidden DEM data can then be sent from the server to a client in order to effect 3D visualization of terrains. The embedding method is integrable with the JPEG2000 coder to accommodate compression and multi-resolution visualization. RĂ©sumĂ© L'utilisation de photographies aĂ©riennes, d'images satellites, de cartes scannĂ©es et de modĂšles numĂ©riques de terrains amĂšne Ă mettre en place des stratĂ©gies de stockage et de visualisation de ces donnĂ©es. Afin d'obtenir une visualisation en trois dimensions, il est nĂ©cessaire de lier ces images appelĂ©es textures avec la gĂ©omĂ©trie du terrain nommĂ©e ModĂšle NumĂ©rique de Terrain (MNT). Ces informations sont en pratiques stockĂ©es dans trois fichiers diffĂ©rents : MNT, texture, position et projection des donnĂ©es dans un systĂšme gĂ©o-rĂ©fĂ©rencĂ©. Dans cet article, nous proposons de stocker toutes ces informations dans un seul fichier afin de les synchroniser. Nous avons dĂ©veloppĂ© pour cela une mĂ©thode d'insertion de donnĂ©es cachĂ©es basĂ©e ondelettes dans une image couleur. Les images de texture contenant les donnĂ©es MNT cachĂ©es peuvent ensuite ĂȘtre envoyĂ©es du serveur au client afin d'effectuer une visualisation 3D de terrains. Afin de combiner une visualisation en multirĂ©solution et une compression, l'insertion des donnĂ©es cachĂ©es est intĂ©grable dans le codeur JPEG 2000
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