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TEMICS Research team

Digital image processing, modeling and communication

  • Leader : Christine Guillemot
  • Research center(s) : CRI Rennes - Bretagne Atlantique
  • Field : Perception, Cognition, Interaction
  • Theme : Vision, Perception and Multimedia Understanding
  • Partner(s) : CNRS,Université Rennes 1

Team presentation

The objectives of the project are to develop concepts and tools in the areas of modelling, coding, communication and watermarking of image and video information handled in multimedia communication.

Research themes

More specifically, our research activities address the following issues:
  • interaction with content and navigation within a 3D representation of the scene captured by a monocular video sequence;
  • image and video source representations that would be compact and robust to noise (packet losses, bit corruption) present on IP or wireless network infrastructures;
  • watermarking for protection against illegal copies and for authentication.

In order to address the above issues, the project activities are structured in three main research themes :

  • Analysis and modelling of video sequencess. This first research line aims at studying suited models of representation for image and video sources. When targeting interaction with the content, a phase of analysis is required. This phase consists in segmenting video objects, in extracting their main attributes (motion, texture, shape, orientation, illumination, ...). Navigating within the scene captured by the video sequence also requires the construction of a 3D model of the scene. The models and attributes extracted must be easy to manipulate. When targeting communication on narrow-band error-prone environments, the representations of these models must be compact and resilient to transmission noise. In order to allow for an easy adaptation to variable constraints linked to the communication channel or to the application, the specified models must be well suited for a granular and hierarchical representation.

  • Joint source and channel coding. The advent of the Internet and of wireless communications, often characterised by narrow-band, error and/or loss prone and heterogeneous channels, is creating challenging problems in the area of video coding. Design principles prevailing so far and stemming from Shannon's source and channel separation theorem are being re-considered. To minimize the impact of the transmission noise on the quality of the reconstructed signal in order to optimize the end-to-end quality of the transmission chain requires to abandon the separation theorem and to consider instead joint source and channel coding strategies. These solutions, considered as viable alternatives for reliable communication over noisy and/or lossy channels, go from a simple joint adjustment of source and channel coding rates to the channel conditions, to a complete re-design of the different operators of a coding scheme. The problematic endorses various characteristics according to the type of channel considered, its loss or error models and according to the application configuration (e.g. real-time interactive or streaming).

  • Watermarking. Watermarking and information hiding refers to nearly invisible embedding of a message within a host signal (text, audio, images or video). It has gained considerable attention in the recent years as a potential solution for a wide range of applications encompassing copyright protection, authentication, and steganography. The watermarking problem can be viewed as a problem of communication over a noisy transmission environment. In the spirit of a communication problem one then seeks the maximum rate of reliable transmission over any hiding and attack strategies. The scientific background of TEMICS in both analysis and joint source and channel coding allows to apprehend efficiently this problematic.

The application domain is multimedia communication over IP and wireless networks

International and industrial relations

The application domain is multimedia communication over IP and wireless networks with their multiple needs in terms of compression, of robust transmission and of advanced functionalities such as navigation, protection and authentication. In this application domain we have industrial collaborations with Thomson Multimedia, France Telecom, Celar We are also involved in national collaborative projects (RNRT COHRAINTE, COSOCATI, OSIAM, V2NET, VISI) and in European collaborative projects (IST-SONG, IST-OPENISE and IST-OZONE). The TEMICS project has also several accademical collaborations on a national level (L2S, I3S) and on an international level (University of illinois at Chicago, Université Catholique de Louvain-La-Neuve).

Keywords: Temics Videocommunication Image sequence Coding Multimedia Numerical television Videowatch Segmentation Motion Projective geometry Quantification Increased reality Networks Internet Quality of servic