Male sperm whale acoustic behavior observed from multipaths at a single hydrophone

Sperm whales generate transient sounds (clicks) when foraging. These clicks have been described as echolocation sounds, a result of having measured the source level and the directionality of these signals and having extrapolated results from biosonar tests made on some small odontocetes. The authors propose a passive acoustic technique requiring only one hydrophone to investigate the acoustic behavior of free-ranging sperm whales. They estimate whale pitch angles from the multipath distribution of click energy. They emphasize the close bond between the sperm whale’s physical and acoustic activity, leading to the hypothesis that sperm whales might, like some small odontocetes, control click level and rhythm. An echolocation model estimating the range of the sperm whale’s targets from the interclick interval is computed and tested during different stages of the whale’s dive. Such a hypothesis on the echolocation process would indicate that sperm whales echolocate their prey layer when initiating their dives and follow a methodic technique when foraging

Joint Lossless Coding and Reversible Data Embedding in a Multiresolution Still Image Coder

International audienceModern still image codecs furnish more than just good distortion-rate performances. They must also provide some services. Scalability in resolution and quality, error resilience and embedded bitstreams were among the first one to be available. There is still room for enhancement, especially when it comes to security-oriented features. Data embedding is necessary, as for inserting metadata, or to copyright a picture. We present the use of a very simple reversible data embedding method in a multiresolution still image codec framework. Experimental results show the usefulness of such an adequation of techniques from different domain. Moreover, the embedding overhead is evaluated and shows to be very acceptable

Embedding Multilevel Image Encryption in the LAR Codec

International audienceA still image codec should not only to be good from compression point of view, it might also provide services. The LAR interleaved S+P codec allows lossless to lossy coding, presenting both resolution and distortion scalability. The proposed method brings image encryption at no cost in the LAR framework. It exploits the embedded quadtree decomposition of the LAR to provide multilevel protection to the whole bit-stream. Theoretical aspects are considered and experimental results show the effectiveness of the process

La RWHT+P pour un codage multirésolution sans perte avancé

Cet article présente une méthode complète de codage sans perte multirésolution, à forte scalabilité sémantique. En particulier, une forme réversible de la classique Transformée de Walsh Hadamard (RWHT) est tout d'abord introduite comme alternative aux transformées sans perte standard. Une représentation pyramidale et des schémas de décomposition reposant sur cette transformée sont ensuite proposés pour un codage multirésolution réversible. Des améliorations significatives y sont apportées en ajoutant deux concepts supplémentaires : la ``résolution localement adaptative'' à travers une représentation quadtree, et une étape de prédiction. Les résultats expérimentaux montrent en final que la méthode RWHT+P proposée aboutit à d'excellentes performances comparées à celles de l'état de l'art

Joint Lossless Coding and Reversible Data Embedding in a Multiresolution Still Image Coder

International audienceModern still image codecs furnish more than just good distortion-rate performances. They must also provide some services. Scalability in resolution and quality, error resilience and embedded bitstreams were among the first one to be available. There is still room for enhancement, especially when it comes to security-oriented features. Data embedding is necessary, as for inserting metadata, or to copyright a picture. We present the use of a very simple reversible data embedding method in a multiresolution still image codec framework. Experimental results show the usefulness of such an adequation of techniques from different domain. Moreover, the embedding overhead is evaluated and shows to be very acceptable

Protection de données à coût nul dans un codeur d'images multirésolution

Les performances des codeurs d'images fixes ne sont plus uniquement évaluées à l'aide des courbes débit-distorsion. Les services fournis sont également un critère de choix. Dans cet article, nous proposons d'intégrer dans un codeur d'images multirésolution offrant des performances supérieures à l'état de l'art avec et sans perte, un schéma de protection de contenu. L'utilisation judicieuse du flux binaire générée par le codeur permet d'obtenir ce service à coût nul. Des éléments tant théoriques que pratiques sont avancés pour justifier l'emploi de ce schéma de protection

Context-Based Scalable Coding and Representation of High Resolution Art Pictures for Remote Data Access

International audienceEROS is the largest database in the world of high resolution art pictures. The TSAR project is designed to open it in a secure, efficient and user-friendly way that involves cryptography and watermarking as well as compression and region-level representation abilities. This paper more particularly addresses the two last points. The LAR codec is first presented as a suitable solution for picture encoding with compression ranging from highly lossy to lossless. Then, we detail the concept of self-extracting region representation, which consists of performing a segmentation process at both the coder and decoder from a highly compressed image, and later locally enhancing the image in a region of interest. The overall scheme provides an efficient, consistent solution for advanced data browsing

A Hierarchical Selective Encryption Technique in a Scalable Image Codec

International audienceModern still image codecs furnish more than just good distortion-rate performances. They must also provide some services. Scalability in resolution and quality, er- ror resilience and embedded bitstreams were among the first one to be available. There is still room for enhance- ment, especially when it comes to security-oriented fea- tures. Image encryption is one of the aspect of image security. This paper presents the embedding of an encryptionservice in a multiresolution lossless codec. Partial encryption is performed using ciphering only the keystone part of the codec algorithm, a quadtree decomposition. This results in a hierarchical encryption scheme, showing to be a good tradeoff between encryption speed, selective access and robustness

A Hierarchical Selective Encryption Technique in a Scalable Image Codec

International audienceModern still image codecs furnish more than just good distortion-rate performances. They must also provide some services. Scalability in resolution and quality, er- ror resilience and embedded bitstreams were among the first one to be available. There is still room for enhance- ment, especially when it comes to security-oriented fea- tures. Image encryption is one of the aspect of image security. This paper presents the embedding of an encryptionservice in a multiresolution lossless codec. Partial encryption is performed using ciphering only the keystone part of the codec algorithm, a quadtree decomposition. This results in a hierarchical encryption scheme, showing to be a good tradeoff between encryption speed, selective access and robustness

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