ZHARP: three-dimensional motion tracking from a single image plane.

Three-dimensional imaging and quantification of myocardial function are essential steps in the evaluation of cardiac disease. We propose a tagged magnetic resonance imaging methodology called zHARP that encodes and automatically tracks myocardial displacement in three dimensions. Unlike other motion encoding techniques, zHARP encodes both in-plane and through-plane motion in a single image plane without affecting the acquisition speed. Postprocessing unravels this encoding in order to directly track the 3-D displacement of every point within the image plane throughout an entire image sequence. Experimental results include a phantom validation experiment, which compares zHARP to phase contrast imaging, and an in vivo study of a normal human volunteer. Results demonstrate that the simultaneous extraction of in-plane and through-plane displacements from tagged images is feasible.

Classification of urban multi-angular image sequences by aligning their manifolds

When dealing with multi-angular image sequences, problems of reflectance changes due either to illumination and acquisition geometry, or to interactions with the atmosphere, naturally arise. These phenomena interplay with the scene and lead to a modification of the measured radiance: for example, according to the angle of acquisition, tall objects may be seen from top or from the side and different light scatterings may affect the surfaces. This results in shifts in the acquired radiance, that make the problem of multi-angular classification harder and might lead to catastrophic results, since surfaces with the same reflectance return significantly different signals. In this paper, rather than performing atmospheric or bi-directional reflection distribution function (BRDF) correction, a non-linear manifold learning approach is used to align data structures. This method maximizes the similarity between the different acquisitions by deforming their manifold, thus enhancing the transferability of classification models among the images of the sequence.

[Rome. Basilica di Santa Maria in Aracoeli]

Référence bibliographique : Weigert, 549

[Rome. Chiesa di Santa Maria di Loreto]

Référence bibliographique : Weigert, 550

[Civitavecchia]

Référence bibliographique : Weigert, 84

[Tarquinia. Tumulo]

Référence bibliographique : Weigert, 95

[Tarquinia. Tombeau étrusque]

Référence bibliographique : Weigert, 97

[Tarquinia. Tumuli]

Référence bibliographique : Weigert, 89

[Nepi. Palazzo comunale, cippe]

Référence bibliographique : Weigert, 293

[Tivoli. Porta Saracena, dite aussi Porta romana]

Référence bibliographique : Weigert, 706

[Tivoli. Tempio di Vesta]

Référence bibliographique : Weigert, 700