Displacement Field

In the paper the modelling of thermo-mechanical effects in the process of friction welding of corundum ceramics and aluminium is presented. The modelling is performed by means of finite element method. The corundum ceramics contains 97% of Al2O3. The mechanical and temperature fields are considered as coupled fields. Simulation of loading of the elements bonded with the heat flux from friction heat on the contact surface is also shown. The heat flux was modified in the consecutive time increments of numerical solutions by changeable pressure on contact surface. Time depending temperature distribution in the bonded elements is also determined. The temperature distribution on the periphery of the cylindrical surfaces of the ceramics and Al was compared to the temperature measurements done with a thermovision camera. The results of the simulation were compared to those obtained from the tests performed by means of a friction welding machine.

Recent advances in imaging technology now provide us with 3D images of developing organs. These can be used to extract 3D geometries for simulations of organ development. To solve models on growing domains, the displacement fields between consecutive image frames need to be determined. Here we develop and evaluate different landmark-free algorithms for the determination of such displacement fields from image data. In particular, we examine minimal distance, normal distance, diffusion-based and uniform mapping algorithms and test these algorithms with both synthetic and real data in 2D and 3D. We conclude that in most cases the normal distance algorithm is the method of choice and wherever it fails, diffusion-based mapping provides a good alternative.

In this paper, we introduce the idea of using motion estimation resources from a video codec for video denoising. This is not straightforward because the motion estimators aimed for video compression and coding, tolerate errors in the estimated motion field and hence are not directly applicable to video denoising. To solve this problem, we propose a novel motion field filtering step that refines the accuracy of the motion estimates to a degree that is required for denoising. We illustrate the use of the proposed motion estimation method within a wavelet-based video denoising scheme. The resulting video denoising method is of low-complexity and receives comparable results with respect to the latest video denoising methods.

Natural selection is the spirit of the genetic algorithm (GA): by keeping the good genes in the current generation, thereby producing better offspring during evolution. The crossover function ensures the heritage of good genes from parent to offspring. Meanwhile, the process of mutation creates a special gene, the character of which does not exist in the parent generation. A program

Résumé/Abstract Depuis plus d'une dizaine d'années, des mesures de vitesses d'écoulement sont effectuées sur le glacier d'Argentière. En complétant avec des mesures plus ponctuelles réalisées lors des expériences MEGATOR, nous avons pu déterminer ...

Owing the phase image method (Hytch, 1998), strain fields can be derived from HREM images. The method is here applied to the nanoscale precipitates responsible for hardening in Aluminum alloys. Since the method is a very sensitive one, we have examined the impact of several aspects of the image quality (noise, fluctuations, distortion). The strain field information derived from the HREM image analysis is further introduced in a simulation of the dislocation motion in the matrix.

Integrating video coding and denoising is a novel processing paradigm, bringing mutual benefits to both video processing tools. In this paper, we propose a novel video denoising approach of which the main idea is reusing motion estimation resources from the video coding module for video denoising. In most cases, the motion fields produced by real-time video codecs cannot be directly employed in video denoising, since they, as opposed to noise filters, tolerate errors in the motion field. In order to solve this problem, we ...

We describe a fully scalable wavelet-based 2D+ t (in-band) video coding architecture. We propose new coding tools specifically designed for this framework aimed at two goals: reduce the computational complexity at the encoder without sacrificing compression; improve the coding efficiency, especially at low bitrates. To this end, we focus our attention on motion estimation and motion vector encoding.

In this paper the representation of three-dimensional displacement fields in linear elasticity in terms of six complex valued functions is considered. The representation includes the complex Muskhelishvili formulation for plane strain as a special case. The completeness of the complex representation for regular solutions is shown and a relationship to the Neuber/Papkovich solutions is given.