One critical aspect to 3D reconstruction of human motion using videogrammetry is related to the n... more One critical aspect to 3D reconstruction of human motion using videogrammetry is related to the need for an accurate calibration of large volumes. Most of calibration methods used in biomechanics requires the construction, transportation and measurement of rigid structures and this is more difficult when larger volumes are involved. Recently, alternative approaches have been proposed to overcome this critical aspect (Cerveri et al., 1998; Zhang, 2000). This work presents preliminary results of the proposition and evaluation of a ...
One of the most challenging problems associated with underwater 3D movement analysis is the accur... more One of the most challenging problems associated with underwater 3D movement analysis is the accurate calibration of the cameras. Additional sources of errors are present in underwater acquisitions such as the nonlinear distortion caused by water interface, camera lenses (ex. wide angle) and housing's glasses. Despite this, in the literature, systems based on a linear calibration model (DLT) were proposed (Yanai et al., 1996; Machtsiras & Sanders, 2009; Gourgoulis, et al. 2008). However, the results of underwater ...
In this work, we propose a framework that allows to build morphological operators for processing ... more In this work, we propose a framework that allows to build morphological operators for processing and filtering objects defined on (abstract) simplicial complex spaces. We illustrate with applications to mesh and image processing, for which, on the provided examples, the proposed approach outperforms the classical one.
We study some basic morphological operators acting on the lattice of all subgraphs of an arbitrar... more We study some basic morphological operators acting on the lattice of all subgraphs of an arbitrary (unweighted) graph G. To this end, we consider two dual adjunctions between the edge set and the vertex set of G. This allows us (i) to recover the classical notion of a dilation/erosion of a subset of the vertices of G and (ii) to extend it to subgraphs of G. Afterward, we propose several new openings, closings, granulometries and alternate filters acting (i) on the subsets of the edge and vertex set of G and (ii) on the subgraphs of G. The proposed framework is then extended to functions that weight the vertices and edges of a graph. We illustrate with applications to binary and grayscale image denoising, for which, on the provided images, the proposed approach outperforms the usual one based on structuring elements.
In this work, we propose a framework that allows to build morphological operators for processing ... more In this work, we propose a framework that allows to build morphological operators for processing and filtering objects defined on (abstract) simplicial complex spaces. We illustrate with applications to mesh and image processing, for which, on the provided examples, the proposed approach outperforms the classical one.
One critical aspect to 3D reconstruction of human motion using videogrammetry is related to the n... more One critical aspect to 3D reconstruction of human motion using videogrammetry is related to the need for an accurate calibration of large volumes. Most of calibration methods used in biomechanics requires the construction, transportation and measurement of rigid structures and this is more difficult when larger volumes are involved. Recently, alternative approaches have been proposed to overcome this critical aspect (Cerveri et al., 1998; Zhang, 2000). This work presents preliminary results of the proposition and evaluation of a ...
One of the most challenging problems associated with underwater 3D movement analysis is the accur... more One of the most challenging problems associated with underwater 3D movement analysis is the accurate calibration of the cameras. Additional sources of errors are present in underwater acquisitions such as the nonlinear distortion caused by water interface, camera lenses (ex. wide angle) and housing's glasses. Despite this, in the literature, systems based on a linear calibration model (DLT) were proposed (Yanai et al., 1996; Machtsiras & Sanders, 2009; Gourgoulis, et al. 2008). However, the results of underwater ...
In this work, we propose a framework that allows to build morphological operators for processing ... more In this work, we propose a framework that allows to build morphological operators for processing and filtering objects defined on (abstract) simplicial complex spaces. We illustrate with applications to mesh and image processing, for which, on the provided examples, the proposed approach outperforms the classical one.
We study some basic morphological operators acting on the lattice of all subgraphs of an arbitrar... more We study some basic morphological operators acting on the lattice of all subgraphs of an arbitrary (unweighted) graph G. To this end, we consider two dual adjunctions between the edge set and the vertex set of G. This allows us (i) to recover the classical notion of a dilation/erosion of a subset of the vertices of G and (ii) to extend it to subgraphs of G. Afterward, we propose several new openings, closings, granulometries and alternate filters acting (i) on the subsets of the edge and vertex set of G and (ii) on the subgraphs of G. The proposed framework is then extended to functions that weight the vertices and edges of a graph. We illustrate with applications to binary and grayscale image denoising, for which, on the provided images, the proposed approach outperforms the usual one based on structuring elements.
In this work, we propose a framework that allows to build morphological operators for processing ... more In this work, we propose a framework that allows to build morphological operators for processing and filtering objects defined on (abstract) simplicial complex spaces. We illustrate with applications to mesh and image processing, for which, on the provided examples, the proposed approach outperforms the classical one.
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Papers by F. Dias