Juan José Villanueva

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ÐIn this paper, we propose an error-tolerant subgraph isomorphism algorithm formulated in terms of Region Adjacency Graphs (RAG). A set of edit operations to transform one RAG into another one are defined. Regions are represented by polylines and string matching techniques are used to measure their similarity. The algorithm follows a branch and bound(More)
Ridges and valleys are useful geometric features for image analysis. Different characterizations have been proposed to formalize the intuitive notion of ridge/valley. In this paper, we review their principal characterizations and propose a new one. Subsequently, we evaluate these characterizations with respect to a list of desirable properties and their(More)
Creases are a type of ridge/valley structures of an image characterized by local conditions. As creases tend to be at the center of anisotropic grey-level shapes, creaseness can be considered a measure of medialness, and therefore as useful in many image analysis problems. Among the several possibilities, a priori the creaseness based on the level-set(More)
RCFL versus Casade on VOC2007: plane bike bird boat bottle bus car cat chair cow table dog horse mbike person plant sheep sofa train tv mean speed Exact 24.1 41.3 11.3 3.9 20.8 36.8 35.4 25.5 16.0 19.4 21.2 23.0 42.9 39.8 24.9 14.6 14.3 33.0 22.8 37.4 25.4 1.0 Cascade 24.1 38.7 12.9 3.9 19.9 37.3 35.7 25.9 16.0 19.3 21.2 23.0 40.2 41.5 24.9 14.6 15.1 33.2(More)
Stent implantation for coronary disease treatment is a highly important minimally invasive technique that avoids surgery interventions. In order to assure the success of such an intervention, it is very important to determine the real length of the lesion as exactly as possible. Currently, lesion measures are performed directly from the angiography without(More)
PCA-like methods make use of an estimation of the covariances between sample variables. This estimation does not take into account their topological relationships. This paper proposes how to use these relationships in order to estimate the covariances in a more robust way. The new method Topological Principal Component Analysis (TPCA) is tested using both(More)
In this paper we propose a human detection framework based on an enhanced version of Histogram of Oriented Gradients (HOG) features. These feature descriptors are computed with the help of a precalculated histogram of square-blocks. This novel method outperforms the integral of oriented histograms allowing the calculation of a single feature four times(More)
Robust and accurate people tracking is a key task in many promising computer-vision applications. One must deal with non-rigid targets in open-world scenarios, whose shape and appearance evolve over time. Targets may interact, causing partial or complete occlusions. This paper improves tracking by means of particle ltering, where occlusions are handled(More)