Paulette Lieby

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Matching and registration of shapes is a key issue in Computer Vision, Pattern Recognition, and Medical Image Analysis. This paper presents a shape representation framework based on Gaussian curvature and Markov random fields (MRFs) for the purpose of shape matching. The method is based on a surface mesh model in R 3 , which is projected into a(More)
In this article, we present a framework to perform statistical shape analysis for segmented hippocampi, including an efficient permutation test for detecting subtle class differences, and a regularized discriminative direction method for visualizing the shape discrepancy. Fisher permutation and bootstrap tests are preferred to traditional hypothesis tests(More)
In some neuroscience applications it is critical that the representation of anatomical structures is topologically faithful. This is especially important when the topology is known to be equivalent to a sphere. We propose a new approach to repair a voxel-based quadrangu-lar mesh so that it becomes topologically equivalent to a sphere. The approach is(More)
Hypothesis testing is an important way to detect the statistical difference between two populations. In this paper, we use the Fisher permutation and bootstrap tests to differentiate hippocampal shape between genders. These methods are preferred to traditional hypothesis tests which impose assumptions on the distribution of the samples. An efficient(More)
An antichain is a collection of sets in which no two sets are comparable under set inclusion. An antichain A is flat if there exists an integer k ≥ 0 such that every set in A has cardinality either k or k + 1. The size of A is |A| and the volume of A is A∈A |A|. The flat antichain theorem states that for any antichain A on [n] = {1, 2,. .. , n} there exists(More)
Let G = G(n) be a randomly chosen k-edge-coloured k-regular graph with 2n vertices, where k = k(n). Equivalently, G is the union of a random set of k disjoint perfect matchings. Let h = h(n) be a graph with m = m(n) edges such that m 2 + mk = o(n). Using a switching argument, we find an asymptotic estimate of the expected number of subgraphs of G isomorphic(More)
Identifying the shape difference between two groups of anatomical objects is important for medical image analysis and computer-aided diagnosis. A method called "discriminative direction" in the literature has been proposed to solve this problem. In that method, the shape difference between groups is identified by deforming a shape along the discriminative(More)
We have tested the potential of three types of vibration motors for use in a tactile vision substitution device for the blind. The motors were of the coin type, which are available off-the-shelf, and are characterized by their affordability, energy efficiency, and ease of implementation. The primary limitation of coin motors is the lack of control they(More)