Henri Maître

Representation and fusion of heterogeneous fuzzy information in the 3D space for model-based structural recognition—application to 3D brain imaging

By Isabelle Bloch, Thierry Géraud, Henri Maître

2003-08-01

In Artificial Intelligence

Abstract

We present a novel approach of model-based pattern recognition where structural information and spatial relationships have a most important role. It is illustrated in the domain of 3D brain structure recognition using an anatomical atlas. Our approach performs simultaneously segmentation and recognition of the scene and the solution of the recognition task is progressive, processing successively different objects, using different of knowledge about the object and about relationships between objects. Therefore the core of the approach is the representation part, and constitutes the main contribution of this paper. We make use of a spatial representation of each piece of information, as a spatial set representing a constraint to be satisfied by the searched object, thanks in particular to fuzzy mathematical operations. Fusion of these constraints allows to, segment and recognize the desired object.

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Error correcting code performance for watermark protection

By Jérôme Darbon, Bulent Sankur, Henri Maître

2001-01-01

In Proceedings of the 13th symposium SPIE on electronic imaging—-security and watermarking of multimedia contents III (EI27)

Abstract

The watermark signals are weakly inserted in images due to imperceptibility constraints which makes them prone to errors in the extraction stage. Although the error correcting codes can potentially improve their performance one must pay attention to the fact that the watermarking channel is in general very noisy. We have considered the trade-off of the BCH codes and repetition codes in various concatenation modes. At the higher rates that can be encountered in watermarking channels such as due to low-quality JPEG compression, codes like the BCH codes cease being useful. Repetition coding seems to be the last resort at these error rates of 25% and beyond. It has been observed that there is a zone of bit error rate where their concatenation turns out to be more useful. In fact the concatenation of repetition and BCH codes judiciously dimensioned, given the available number of insertion sites and the payload size, achieves a higher reliability level.

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