Video transmission over noisy wireless channels leads to errors on video, which degrades the visual quality notably and makes error concealment an indispensable job. In the literature, there are several error concealment techniques based on estimating the lost parts of the video from the available data. Utilization of data hiding for this problem, which seems to be an alternative of predicting the lost data, provides a reserve information about the video to the receiver while unchanging the transmitted bit-stream syntax / hence, improves the reconstruction video quality without significant extra channel utilization. A complete error resilient video transmission codec is proposed, utilizing imperceptible embedded information for combined detecting, resynchronization and reconstruction of the errors and lost data. The data, which is imperceptibly embedded into the video itself at the encoder, is extracted from the video at the decoder side to be utilized in error concealment. A spatial domain error recovery technique, which hides edge orientation information of a block, and a resynchronization technique, which embeds bit length of a block into other blocks are combined, as well as some parity information about the hidden data, to conceal channel errors on intra-coded frames of a video sequence. The errors on inter-coded frames are basically recovered by hiding motion vector information along with a checksum into the next frames. The simulation results show that the proposed approach performs superior to conventional approaches for concealing the errors in binary symmetric channels, especially for higher bit rates and error rates.

In my master's thesis I start fromthedescriptionofthebasics and thebeginningsofsteganography, itsmethods and purposes. Detaileddescriptionof BMP fileswithhidden data follows. A filestructureisanalysedintothesmallestdetails to avoiddamagingfilewhilehiding. At thesametime to make profit oftheinformationincluded in a fileheader in the most effectiveway. Anotheraimwas to explain a principalofsteganographicalmethoditself, usedforhiding data into BMP file. Based on these findings, a programmeconceptwasdesigned and consequentlythatprogrammewas made. Itcarriesoutthehiding and revealing data intothe image files. Directionsfor use are made to thisprogramme and thereisalso a demo ofthefeaturesdescribingeach step. At the end ofmymaster's thesis anattentionispaid to thoseinfluencesthatcanbelimitingforthismethod. Exceeding these limitswouldlead to breakingthesteganographicalmethod, whichmeansrevealingthehidden data.

The diploma thesis aims on the matter of data hiding (steganography) in audio records. It describes general steganographic principles and aims further on the specifics of data hiding in audio records and also aims on the LSB steganographic technique and suitability of different types of audio records to be used with this technique. The thesis also describes a laboratory exercise focused on steganography in audio records and influence of related aspects on the final audio record which contains secret data. Further, the thesis describes a program that was created especially for the laboratory exercise, from the design, functional as well as implementation-related view. Within the exercise, students will be able to examine how the amount of data to be hidden in the audio record and different ways of data hiding will affect quality of the resulting audio record, and therefore they can become more familiar with the matter of steganography based on the LSB method used in audio records.

<p>Data embedding tools such as barcodes are very popular nowadays but not aesthetically pleasing. In this research, we propose a watermarking scheme and an image-based surface coding scheme using the grid points as fiducial markers and the shifted points as data-bearing features. Detecting and aligning point grids play a fundamental role in these applications. Joint determination of non-grid points and estimation of non-linear spatial distortions applied to the grid is a key challenge for grid alignment. We modify a SIFT-based surface feature detection method to eliminate as many spurious feature points as possible and propose a grid alignment algorithm that starts from a small nearly regular region found in the point set and then expands the list of candidate points included in the grid. Our method is tested on both synthetically generated and real samples. Furthermore, we extend some applications of the surface coding scheme to 3D space, including hyper-conformal mapping of the grid pattern onto the 3D models, 3D surface feature detection, and 3D grid points alignment. </p> <p>A document routing system is crucial to the concept of the smart office. We abstract it as an online class-incremental image classification problem. There are two kinds of classifiers to solve this problem: exemplar, and parametric classifiers. The architecture of exemplar-based classification is summarized here. We propose a one-versus-rest parametric classifier and four different updating algorithms based on the passive-aggressiveness algorithm. An adaptive thresholding method is also proposed to indicate the low-confidence prediction. We test our methods on 547 real document images that we collected and labeled and high cumulative accuracy is reported. </p>

Cette thèse aborde les problèmes liés à la protection de maillages d'objets 3D. Ces objets peuvent, par exemple, être créés à l'aide d'outil de CAD développés par la société STRATEGIES. Dans un cadre industriel, les créateurs de maillages 3D ont besoin de disposer d'outils leur permettant de vérifier l'intégrité des maillages, ou de vérifier des autorisations pour l'impression 3D par exemple. Dans ce contexte nous étudions l'insertion de données cachées dans des maillages 3D. Cette approche permet d'insérer de façon imperceptible et sécurisée de l'information dans un maillage. Il peut s'agir d'un identifiant, de méta-informations ou d'un contenu tiers, par exemple, pour transmettre de façon secrète une texture. L'insertion de données cachées permet de répondre à ces problèmes en jouant sur le compromis entre la capacité, l'imperceptibilité et la robustesse. Généralement, les méthodes d'insertion de données cachées se composent de deux phases, la synchronisation et l'insertion. La synchronisation consiste à trouver et ordonner les éléments disponibles pour l'insertion. L'un des principaux challenges est de proposer une méthode de synchronisation 3D efficace qui définit un ordre sur les composants des maillages. Dans nos travaux, nous proposons d'utiliser les sommets du maillage, plus précisément leur représentation géométrique dans l'espace comme composants de base pour la synchronisation et l'insertion. Nous présentons donc trois nouvelles méthodes de synchronisation de la géométrie des maillages basées sur la construction d'un chemin hamiltonien dans un nuage de sommets. Deux de ces méthodes permettent de manière conjointe de synchroniser les sommets et de cacher un message. Cela est possible grâce à deux nouvelles méthodes d'insertion haute capacité (de $3$ à $24$ bits par sommet) qui s'appuient sur la quantification des coordonnées. Dans ces travaux nous mettons également en évidence les contraintes propres à ce type de synchronisation. Nous discutons des différentes approches proposées dans plusieurs études expérimentales. Nos travaux sont évalués sur différents critères dont la capacité et l'imperceptibilité de la méthode d'insertion. Nous portons également notre attention aux aspects sécurité des méthodes. / This thesis addresses issues relating to the protection of 3D object meshes. For instance, these objects can be created using CAD tool developed by the company STRATEGIES. In an industrial context, 3D meshes creators need to have tools in order to verify meshes integrity, or check permission for 3D printing for example.In this context we study data hiding on 3D meshes. This approach allows us to insert information in a secure and imperceptible way in a mesh. This may be an identifier, a meta-information or a third-party content, for instance, in order to transmit secretly a texture. Data hiding can address these problems by adjusting the trade-off between capacity, imperceptibility and robustness. Generally, data hiding methods consist of two stages, the synchronization and the embedding. The synchronization stage consists of finding and ordering available components for insertion. One of the main challenges is to propose an effective synchronization method that defines an order on mesh components. In our work, we propose to use mesh vertices, specifically their geometric representation in space, as basic components for synchronization and embedding. We present three new synchronisation methods based on the construction of a Hamiltonian path in a vertex cloud. Two of these methods jointly perform the synchronization stage and the embedding stage. This is possible thanks to two new high-capacity embedding methods (from 3 to 24 bits per vertex) that rely on coordinates quantization. In this work we also highlight the constraints of this kind of synchronization. We analyze the different approaches proposed with several experimental studies. Our work is assessed on various criteria including the capacity and imperceptibility of the embedding method. We also pay attention to security aspects of the proposed methods.

Esteganografia é uma técnica utilizada para ocultar uma informação secreta dentro de outro tipo de informação sem perda de qualidade da informação hospedeira e com o objetivo de extrair a informação posteriormente. Esteganografia reversível permite a exata restauração (sem perda) do sinal hospedeiro original após a extração da informação oculta. Várias ténicas reversíveis têm sido desenvolvidas, mas nenhuma delas parece ser apropriada para imagens binárias. Uma técnica de marca d\'água faz uso de técnicas esteganográficas para inserir informação em uma imagem hospedeira, com o intuito de fazer uma asserção sobre a imagem no futuro. Uma marca d\'água de autenticação (AWT) insere uma informação oculta na imagem com a intenção de detectar qualquer alteração acidental ou maliciosa na imagem. Uma AWT normalmente usa criptografia de chave secreta ou chave pública para computar a assinatura de autenticação da imagem, inserindo-a na própria imagem. JBIG2 é um padrão internacional para compressão de imagens binárias (com ou sem perda). Ele decompõe a imagem em várias regiões (texto, meio-tom e genérica) e codifica cada região usando o método mais apropriado. A criação de AWTs seguras para imagens binárias comprimidas é um importante problema prático. Porém, parece que nenhuma AWT para JBIG2 já foi proposta. Este trabalho propõe algumas técnicas esteganográficas para arquivos JBIG2. Então, estas técnicas são usadas para criar AWTs para imagens codificadas como JBIG2. As imagens marcadas são visualmente agradáveis, sem ruídos do tipo sal-e-pimenta. Este trabalho também propõe uma técnica esteganográfica reversível para imagens binárias. A técnica proposta seleciona um conjunto de pixels de baixa visibilidade e utiliza o algoritmo de Golomb para comprimir as previsões desses pixels. Então, a informação comprimida e a informação a ser oculta são inseridas na imagem. Imagens marcadas com a técnica proposta possuem excelente qualidade visual, pois apenas pixels de baixa visibilidade são modificados. Então, a técnica proposta é utilizada para autenticar imagens binárias e documentos de maneira reversível. / Data-hiding is a technique to hide secret information inside another group of information data, without loss of quality of the host information, and the means to extract the secret information afterwards. Reversible data-hiding enable the exact restoration (lossless) of the original host signal after extracting the embedded information. Several reversible data hiding techniques have been developed, but none of them seems to be appropriate for binary images. A watermarking technique makes use of data-hiding to insert some information into the host image, in order to make a posterior assertion about the image. An authentication watermarking technique (AWT) inserts hidden data into an image in order to detect any accidental or malicious alteration to the image. AWT normally makes use of secret- or publickey cryptographic ciphers to compute the authentication signature of the image, and inserts it into the image itself. JBIG2 is an international standard for compressing bilevel images in both lossy and lossless modes. JBIG2 decomposes the image into several regions (text, halftone and generic) and encodes each one using the most appropriate method. The creation of secure AWTs for compressed binary images is an important practical problem. However, it seems that no AWT for JBIG2 has ever been proposed. This work proposes some data-hiding techniques for JBIG2 files. Then, these techniques are used to design AWTs for JBIG2-encoded images. The resulting watermarked images are visually pleasant, without visible salt and pepper noise. This work also proposes a reversible data hiding technique for binary images. The proposed technique selects a set of low-visibility pixels and uses Golomb codes to compress the predictions of these pixels. Then, this compressed data and the net payload data are embedded into the image. Images watermarked by the proposed technique have excellent visual quality, because only low-visibility pixels are flipped. Then, the proposed data hiding is used to reversibly authenticate binary images and documents.

Esteganografia é uma técnica utilizada para ocultar uma informação secreta dentro de outro tipo de informação sem perda de qualidade da informação hospedeira e com o objetivo de extrair a informação posteriormente. Esteganografia reversível permite a exata restauração (sem perda) do sinal hospedeiro original após a extração da informação oculta. Várias ténicas reversíveis têm sido desenvolvidas, mas nenhuma delas parece ser apropriada para imagens binárias. Uma técnica de marca d\'água faz uso de técnicas esteganográficas para inserir informação em uma imagem hospedeira, com o intuito de fazer uma asserção sobre a imagem no futuro. Uma marca d\'água de autenticação (AWT) insere uma informação oculta na imagem com a intenção de detectar qualquer alteração acidental ou maliciosa na imagem. Uma AWT normalmente usa criptografia de chave secreta ou chave pública para computar a assinatura de autenticação da imagem, inserindo-a na própria imagem. JBIG2 é um padrão internacional para compressão de imagens binárias (com ou sem perda). Ele decompõe a imagem em várias regiões (texto, meio-tom e genérica) e codifica cada região usando o método mais apropriado. A criação de AWTs seguras para imagens binárias comprimidas é um importante problema prático. Porém, parece que nenhuma AWT para JBIG2 já foi proposta. Este trabalho propõe algumas técnicas esteganográficas para arquivos JBIG2. Então, estas técnicas são usadas para criar AWTs para imagens codificadas como JBIG2. As imagens marcadas são visualmente agradáveis, sem ruídos do tipo sal-e-pimenta. Este trabalho também propõe uma técnica esteganográfica reversível para imagens binárias. A técnica proposta seleciona um conjunto de pixels de baixa visibilidade e utiliza o algoritmo de Golomb para comprimir as previsões desses pixels. Então, a informação comprimida e a informação a ser oculta são inseridas na imagem. Imagens marcadas com a técnica proposta possuem excelente qualidade visual, pois apenas pixels de baixa visibilidade são modificados. Então, a técnica proposta é utilizada para autenticar imagens binárias e documentos de maneira reversível. / Data-hiding is a technique to hide secret information inside another group of information data, without loss of quality of the host information, and the means to extract the secret information afterwards. Reversible data-hiding enable the exact restoration (lossless) of the original host signal after extracting the embedded information. Several reversible data hiding techniques have been developed, but none of them seems to be appropriate for binary images. A watermarking technique makes use of data-hiding to insert some information into the host image, in order to make a posterior assertion about the image. An authentication watermarking technique (AWT) inserts hidden data into an image in order to detect any accidental or malicious alteration to the image. AWT normally makes use of secret- or publickey cryptographic ciphers to compute the authentication signature of the image, and inserts it into the image itself. JBIG2 is an international standard for compressing bilevel images in both lossy and lossless modes. JBIG2 decomposes the image into several regions (text, halftone and generic) and encodes each one using the most appropriate method. The creation of secure AWTs for compressed binary images is an important practical problem. However, it seems that no AWT for JBIG2 has ever been proposed. This work proposes some data-hiding techniques for JBIG2 files. Then, these techniques are used to design AWTs for JBIG2-encoded images. The resulting watermarked images are visually pleasant, without visible salt and pepper noise. This work also proposes a reversible data hiding technique for binary images. The proposed technique selects a set of low-visibility pixels and uses Golomb codes to compress the predictions of these pixels. Then, this compressed data and the net payload data are embedded into the image. Images watermarked by the proposed technique have excellent visual quality, because only low-visibility pixels are flipped. Then, the proposed data hiding is used to reversibly authenticate binary images and documents.

Digital steganography is a technique for hiding data mostly into multimedia files (images, audio, video). With the development of information technology this technique has found its use in the field of copyright protection and secret data transfer, could be even applied in places where is limited possibility of using cryptography (e. g. by law). This thesis gives insight into digital steganography and contains an application using this technique.

Une des préoccupations dans le domaine des communications sécurisées est le concept de sécurité de l'information. Aujourd’hui, la réalité a encore prouvé que la communication entre deux parties sur de longues distances a toujours été sujet au risque d'interception. Devant ces contraintes, de nombreux défis et opportunités s’ouvrent pour l'innovation. Afin de pouvoir fournir une communication sécurisée, cela a conduit les chercheurs à développer plusieurs schémas de stéganographie. La stéganographie est l’art de dissimuler un message de manière secrète dans un support anodin. L’objectif de base de la stéganographie est de permettre une communication secrète sans que personne ne puisse soupçonner son existence, le message secret est dissimulé dans un autre appelé medium de couverture qui peut être image, video, texte, audio,…. Cette propriété a motivé les chercheurs à travailler sur ce nouveau champ d’étude dans le but d’élaborer des systèmes de communication secrète résistante à tout type d’attaques. Cependant, de nombreuses techniques ont été développées pour dissimuler un message secret dans le but d’assurer une communication sécurisée. Les contributions majeures de cette thèse sont en premier lieu, de présenter une nouvelle méthode de stéganographie permettant la dissimulation d’un message secret dans un signal de parole. La dissimulation c’est le processus de cacher l’information secrète de façon à la rendre imperceptible pour une partie tierce, sans même pas soupçonner son existence. Cependant, certaines approches ont été étudiées pour aboutir à une méthode de stéganogaraphie robuste. En partant de ce contexte, on s’est intéressé à développer un système de stéganographie capable d’une part de dissimuler la quantité la plus élevée de paramètre tout en gardant la perceptibilité du signal de la parole. D’autre part nous avons opté pour la conception d’un algorithme de stéganographie assez complexe afin d’assurer l’impossibilité d’extraction de l’information secrète dans le cas ou son existence été détecter. En effet, on peut également garantir la robustesse de notre technique de stéganographie à l’aptitude de préservation du message secret face aux tentatives de détection des systèmes de stéganalyse. Notre technique de dissimulation tire son efficacité de l’utilisation de caractéristiques spécifiques aux signaux de parole et àl’imperfection du système auditif humain. Des évaluations comparatives sur des critères objectifs et subjectifs de qualité sont présentées pour plusieurs types de signaux de parole. Les résultats ont révélé l'efficacité du système développé puisque la technique de dissimulation proposée garantit l’imperceptibilité du message secret voire le soupçon de son existence. Dans la suite expérimentale et dans le même cadre de ce travail, la principale application visée par la thèse concerne la transmission de parole sécurisée par un algorithme de stéganographie. Dans ce but il s’est avéré primordial d’utiliser une des techniques de codage afin de tester la robustesse de notre algorithme stéganographique face au processus de codage et de décodage. Les résultats obtenus montrent la possibilité de reconstruction du signal original (contenant des informations secrètes) après codage. Enfin une évaluation de la robustesse de notre technique de stéganographie vis à vis des attaques est faite de façon à optimiser la technique afin d'augmenter le taux de sécurisation. Devant cette nécessité nous avons proposé une nouvelle technique de stéganalyse basée sur les réseaux de neurones AR-TDNN. La technique présentée ici ne permet pas d'extraire l'éventuel message caché, mais simplement de mettre en évidence sa présence. / One of the concerns in the field of secure communication is the concept of information security. Today’s reality is still showing that communication between two parties over long distances has always been subject to interception. Providing secure communication has driven researchers to develop several cryptography schemes. Cryptography methods achieve security in order to make the information unintelligible to guarantee exclusive access for authenticated recipients. Cryptography consists of making the signal look garbled to unauthorized people. Thus, cryptography indicates the existence of a cryptographic communication in progress, which makes eavesdroppers suspect the existence of valuable data. They are thus incited to intercept the transmitted message and to attempt to decipher the secret information. This may be seen as weakness in cryptography schemes. In contrast to cryptography, steganography allows secret communication by camouflaging the secret signal in another signal (named the cover signal), to avoid suspicion. This quality motivated the researchers to work on this burning field to develop schemes ensuring better resistance to hostile attackers. The word steganography is derived from two Greek words: Stego (means cover) and graphy (means writing). The two combined words constitute steganography, which means covert writing, is the art of hiding written communications. Several steganography techniques were used to send message secretly during wars through the territories of enemies. The major contributions of this thesis are the following ones. We propose a new method to secure speech communication using the Discrete Wavelet Transforms (DWT) and the Fast Fourier Transform (FFT). Our method exploits first the high frequencies using a DWT, then exploits the low-pass spectral properties of the speech magnitude spectrum to hide another speech signal in the low-amplitude high-frequencies region of the cover speech signal. The proposed method allows hiding a large amount of secret information while rendering the steganalysis more complex. Comparative evaluation based on objective and subjective criteria is introduced for original speech signal, stego-signal and reconstructed secret speech signal after the hiding process. Experimental simulations on both female and male speakers revealed that our approach is capable of producing a stego speech that is indistinguishable from the cover speech. The receiver is still able to recover an intelligible copy of the secret speech message. We used an LPC10 coder to test the effect of the coding techniques on the stego-speech signals. Experimental results prove the efficiency of the used coding technique since intelligibility of the stego-speech is maintained after the encoding and decoding processes. We also advocate a new steganalysis technique to ensure the robustness of our steganography method. The proposed classifier is called Autoregressive time delay neural network (ARTDNN). The purpose of this steganalysis system is to identify the presence or not of embedded information, and does not actually attempt to extract or decode the hidden data. The low detecting rate prove the robustness of our hiding technique.

Les technologies numériques et du multimédia ont connu de grandes avancées ces dernières années. La chaîne de transmission des images est constituée de plusieurs traitements divers et variés permettant de transmettre un flux de données toujours plus grand avec toujours plus de services à la clé. Nous citons par exemple, la compression, l'augmentation de contenu, la confidentialité, l'intégrité et l'authenticité des images pendant leur transmission. Dans ce contexte, les approches conjointes ont suscité un intérêt certain de la part de la communauté du traitement d'images car elles permettent d'obtenir des systèmes de faible complexité calculatoire pouvant être utilisés dans des applications nécessitant peu de ressources matérielles. La dissimulation de données ou Data Hiding, est l'art de cacher un message dans un support numérique. L'une des branches les plus importantes du data hiding est le tatouage numérique ou watermarking. La marque doit rester présente dans l'image hôte même si celle-ci subit des modifications appelées attaques. La compression d'images a comme objectif de réduire la taille des images stockées et transmises afin d'augmenter la capacité de stockage et de minimiser le temps de transmission. La compression représente une opération incontournable du stockage ou du transfert d'images. Elle est considérée par le data hiding comme une attaque particulièrement destructrice. La norme JPEG2000 est le dernier standard ISO/ITU-T pour le codage des images fixes. Dans cette thèse, nous étudions de manière conjointe la compression avec perte et le data hiding dans le domaine JPEG2000. L'approche conjointe offre de nombreux avantages dont le plus important est que la compression ne constitue plus une attaque vis-à-vis du data hiding. Les contraintes à respecter sont exprimées en termes de compromis à atteindre: compromis entre la quantité d'information insérée (payload), le taux de compression, la distorsion induite par l'insertion du message et la robustesse de la marque dans le cas du tatouage.Nos travaux de recherche ont conduit à l'élaboration de plusieurs schémas conjoints : un schéma conjoint d'insertion de données cachées et deux schémas conjoints de tatouage dans JPEG2000. Tous ces systèmes conjoints reposent sur des stratégies d'insertion informée basées sur la quantification codée par treillis (TCQ). Les propriétés de codage de canal de la TCQ sont exploitées pour pouvoir à la fois quantifier et insérer un message caché (ou une marque) pendant l'étape de quantification de JPEG2000. / Technological advances in the fields of telecommunications and multimedia during the two last decades, derive to create novel image processing services such as copyright protection, data enrichment and information hiding applications. There is a strong need of low complexity applications to perform seveval image processing services within a single system. In this context, the design of joint systems have attracted researchers during the last past years. Data hiding techniques embed an invisible message within a multimedia content by modifying the media data. This process is done in such a way that the hidden data is not perceptible to an observer. Digital watermarking is one type of data hiding. The watermark should be resistant to a variety of manipulations called attacks. The purpose of image compression is to represent images with less data in order to save storage costs or transmission time. Compression is generally unavoidable for transmission or storage purposes and is considered as one of the most destructive attacks by the data hiding. JPEG2000 is the last ISO/ ITU-T standard for still image compression.In this thesis, joint compression and data hiding is investigated in the JPEG2000 framework. Instead of treating data hiding and compression separately, it is interesting and beneficial to look at the joint design of data hiding and compression system. The joint approach have many advantages. The most important thing is that compression is no longer considered as an attack by data hiding.The main constraints that must be considered are trade offs between payload, compression bitrate, distortion induced by the insertion of the hidden data or the watermark and robustness of watermarked images in the watermarking context. We have proposed several joint JPEG2000 compression and data hiding schemes. Two of these joint schemes are watermarking systems. All the embedding strategies proposed in this work are based on Trellis Coded Quantization (TCQ). We exploit the channel coding properties of TCQ to reliably embed data during the quantization stage of the JPEG2000 part 2 codec.