The paper presents investigations concerning an important problem of mobile robot control using visual feedback. Two main topics are considered: a collision-free path planning and posture tracking on the basis of pictures obtained from static monochromatic camera. A collision-free path is determined off-line in multiprocessor system using the artificial potential field method. Parallel algorith...

A method for generating geometric surface meshes from a discrete surface, called a reference mesh, is presented. First, the geometrical singularities are extracted from the reference mesh. Then, an almost smooth surface interpolating the reference mesh vertices is associated to the reference mesh. Finally, the reference mesh is adaptively refined via the smooth geometry in order to obtain an ad...

Digital multimedia content protection has increasingly become an important issue. Because image watermarking is identified as a major technology used in copyright protection, a key requirement for image watermarking is the development of its imperceptibility and robustness. To meet this requirement, a novel robust image watermarking scheme based on discrete wavelet transform (DWT), singular val...

A new linear-features detection method is proposed for extracting straight edges and lines in synthetic-aperture radar images. This method is based on the localized Radon transform, which produces geometrical integrals along straight lines. In the transformed domain, linear features have a specific signature: They appear as strongly contrasted structures, which are easier to extract with the co...

An algorithm for speaker's lip segmentation and features extraction is presented in this paper. A c olor video s e quence o f s p e aker's face i s a c quired, under natural lighting conditions and without any particular make-up. First, a logarithmic color transform is performed f r om RGB to HI hue, intensity color space. Second, a statistical approach using Markov random eld modeling determin...

This paper introduces orthogonal bandelet bases to approximate images having some geometrical regularity. These bandelet bases are computed by applying parametrized Alpert transform operators over an orthogonal wavelet basis. These bandeletization operators depend upon a multiscale geometric flow that is adapted to the image at each wavelet scale. This bandelet construction has a hierarchical s...

ABSTRACT Differential operators have been widely used for multiscale geometric descriptions of images. Efficient computation of these differential operators can be obtained by taking advantage of the spline techniques. In this paper, we make use of a special class of these operators for image enhancement, with a particular application to chromosome image enhancement. These operators constitute ...

This paper describes the detection of faces in complex backgrounds where their sizes, positions and directions are arbitrary. We detect the faces by extracting face components such as eyes, a mouth and so on. We first extract face features and then calculate their likelihoods as each face component. Second we detect the face features which satisfy geometrical relations of the face. In order to ...

The basics of interferometry are covered in these lectures. We first discuss a simple interferometer and show that the output is proportional to the Fourier transform of the sky brightness. This leads to the concept of aperture synthesis. The geometrical effects of Earth rotation. the idea of fringe frequency and the resolution or (u,v) plane are then discussed. Finally the formation of images ...

The analytical Fourier-Mellin transform is used in order to assess motion parameters between gray-level objects having the same shape with distinct scale and orientation. From results on commutative harmonic analysis, a functional is constructed in which the location of the minimum gives an estimation of the size and orientation parameters. Furthermore, when the set of geometrical transformatio...