The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform

Joachim Dengler - One of the best experts on this subject based on the ideXlab platform.

  • Estimation of discontinuous Displacement vector fields with the minimum description length criterion
    Proceedings. 1991 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 1991
    Co-Authors: Joachim Dengler
    Abstract:

    A noniterative approach to Determine Displacement vector fields with discontinuities is described. In order to overcome the limitations of current methods, the problem is regarded as a general modeling problem. From this point of view the imaging field consists of a set of regions with common properties and their boundaries. The strategy proposed is an analysis of consistency of the Displacement estimators between different levels of regularization. This gives local but noisy evidence of possible model boundaries at multiple scales. With the two constraints of continuous lines of discontinuities and the spatial coincidence assumption, consistent boundary evidence is found. Based on this combined evidence the model is updated so that it describes homogeneous regions with sharp discontinuities.

  • CVPR - Estimation of discontinuous Displacement vector fields with the minimum description length criterion
    1991
    Co-Authors: Joachim Dengler
    Abstract:

    A noniterative approach to Determine Displacement vector fields with discontinuities is described. In order to overcome the limitations of current methods, the problem is regarded as a general modeling problem. From this point of view the imaging field consists of a set of regions with common properties and their boundaries. The strategy proposed is an analysis of consistency of the Displacement estimators between different levels of regularization. This gives local but noisy evidence of possible model boundaries at multiple scales. With the two constraints of continuous lines of discontinuities and the spatial coincidence assumption, consistent boundary evidence is found. Based on this combined evidence the model is updated so that it describes homogeneous regions with sharp discontinuities. >

  • Estimation of Discontinuous Displacement Vector Fields with the Minimum Description Length Criterion
    1990
    Co-Authors: Joachim Dengler
    Abstract:

    A new noniterative approach to Determine Displacement vector fields with discontinuities is described. In order to overcome the limitations of current methods, the problem is regarded as a general modelling problem. Starting from a family of regularized estimates, by measuring the difference in description length the compatibility between different levels of regularization is Determined. This gives local but noisy evidence of possible model boundaries at multiple scales. With the two constraints of continous lines of discontinuities and the spatial coincidence assumption consistent boundary evidence is found. Based on this combined evidence the model is updated, now describing homogeneous regions with sharp discontinuities.

Stephane Roux - One of the best experts on this subject based on the ideXlab platform.

  • Shear-band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2020
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    International audienceFinite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the eXtended Finite Element Method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert-Lüders bands

  • shear band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2007
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    Abstract Finite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the extended finite element method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert–Luders bands.

Julien Rethore - One of the best experts on this subject based on the ideXlab platform.

  • Shear-band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2020
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    International audienceFinite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the eXtended Finite Element Method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert-Lüders bands

  • shear band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2007
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    Abstract Finite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the extended finite element method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert–Luders bands.

Francois Hild - One of the best experts on this subject based on the ideXlab platform.

  • Shear-band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2020
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    International audienceFinite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the eXtended Finite Element Method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert-Lüders bands

  • shear band capturing using a multiscale extended digital image correlation technique
    Computer Methods in Applied Mechanics and Engineering, 2007
    Co-Authors: Julien Rethore, Francois Hild, Stephane Roux
    Abstract:

    Abstract Finite elements have been used recently to solve the optical flow conservation principle invoked to Determine Displacement fields by digital image correlation. Inspired by these recent advances, and by the computational effort that has been accomplished during the past 10 years for the simulation of discontinuities by the extended finite element method (XFEM), an extended correlation technique is introduced for capturing shear-band like discontinuities from images of real mechanical tests. Because of the specific information at hand (i.e., gray level images), this extended finite element approach is included in a non-linear multi-grid solver. The performances of the proposed approach are discussed on two examples, namely the analysis of a bolted assembly and the formation of Piobert–Luders bands.

Vitor Filipe - One of the best experts on this subject based on the ideXlab platform.

  • cross correlation and differential technique combination to Determine Displacement fields
    Strain, 2011
    Co-Authors: Antonio M R Sousa, J Xavier, J J L Morais, Vitor Filipe
    Abstract:

    :  This study presents a method to measure the Displacement fields on the surface of planar objects with sub-pixel resolution, by combining image correlation with a differential technique. First, a coarse approximation of the pixel level Displacement is obtained by cross-correlation (CC). Two consecutive images, taken before and after the application of a given deformation, are recursively split in sub-images, and the CC coefficient is used as the similarity measure. Secondly, a fine approximation is performed to assess the sub-pixel Displacements by means of an optical flow method based on a differential technique. To validate the effectiveness and robustness of the proposed method, several numerical tests were carried out on computer-generated images. Moreover, real images from a static test were also processed for estimating the Displacement resolution. The results were compared with those obtained by a commercial digital image correlation code. Both methods showed similar and reliable results according to the proposed tests.

  • Cross‐Correlation and Differential Technique Combination to Determine Displacement Fields
    Strain, 2010
    Co-Authors: Antonio M R Sousa, J Xavier, J J L Morais, Vitor Filipe
    Abstract:

    :  This study presents a method to measure the Displacement fields on the surface of planar objects with sub-pixel resolution, by combining image correlation with a differential technique. First, a coarse approximation of the pixel level Displacement is obtained by cross-correlation (CC). Two consecutive images, taken before and after the application of a given deformation, are recursively split in sub-images, and the CC coefficient is used as the similarity measure. Secondly, a fine approximation is performed to assess the sub-pixel Displacements by means of an optical flow method based on a differential technique. To validate the effectiveness and robustness of the proposed method, several numerical tests were carried out on computer-generated images. Moreover, real images from a static test were also processed for estimating the Displacement resolution. The results were compared with those obtained by a commercial digital image correlation code. Both methods showed similar and reliable results according to the proposed tests.