We propose a Bayesian approach to learn finite generalized inverted Dirichlet mixture models. The developed approach performs simultaneous parameters estimation, model complexity determination, and feature selection via a reversible jump Markov Chain Monte Carlo (RJMCMC) algorithm. A challenging application that concerns video forgery detection is deployed to validate our statistical framework and to show its merits.

In this paper we present a new Smart Online Vehicle Tracking System for Security Applications (AMOTSSA) and we describe how it can be modelled and implemented as a Big data application. In order to model AMOTSSA as a big data application, we argue our design choices that meets its specific data and processing needs and we present a set of data analytic algorithms that would achieve a set of investigation support goals.

Beta-Liouville mixture models have achieved measurable success in many computer vision and pattern recognition applications. In this paper, we develop a novel algorithm to learn this particular kind of models that have been shown to be very efficient for the clustering of proportional data. Our algorithm is based on an accelerated version of the variational Bayes approach. Experiments show that the developed algorithm work very well for the categorization of 3D shapes.

In this paper, we formulate 3D model recognition as a statistical inference problem using a Pitman-Yor process mixture of Beta-Liouville Distributions. The proposed model is learned via a collapsed variational inference approach. Unlike classic variational Bayes, the collapsed approach does not make the non-realistic assumption that the model's parameters are independent from the assignment variables, which leads to better modelling and generalization capabilities. The merits and advantages of the proposed approach are shown via extensive experiments.

In this paper, a novel approach to local 3D surface matching representation suitable for a range of 3D vision applications is introduced. Local 3D surface patches around key points on the 3D surface are represented by 2D images such that the representing 2D images enjoy certain characteristics which positively impact the matching accuracy, robustness, and speed. First, the proposed representation is complete, in the sense, there is no information loss during their computation. Second, the 3DoF 2D representations are strictly invariant to all the 3DoF rotations. To optimally avail surface information, the sensitivity of the representations to surface information is adjustable. This also provides the proposed matching representation with the means to optimally adjust to a particular class of problems/applications or an acquisition technology. Each 2D matching representation is a sequence of adjustable integral kernels, where each kernel is efficiently computed from a triple of precise 3D curves (profiles) formed by intersecting three concentric spheres with the 3D surface. Robust techniques for sampling the profiles and establishing correspondences among them were devised. Based on the proposed matching representation, two techniques for the detection of key points were presented. The first is suitable for static images, while the second is suitable for 3D videos. The approach was tested on the face recognition grand challenge v2.0, the 3D twins expression challenge, and the Bosphorus data sets, and a superior face recognition performance was achieved. In addition, the proposed approach was used in object class recognition and tested on a Kinect data set.

It is well-known that classification tasks can be approached using either generative models or discriminative ones. While the goal of generative approaches is to learn class-conditional densities, the main goal of discriminative techniques is to learn decision boundaries directly without taking into account class-conditional densities. In classic supervised learning, we would usually represent a given object (an image, for instance) by a vector of D real-valued features and then select a given generative or discriminative approach to perform classification. In many applications, however, the object can be represented by a set (or) bag of vectors. Recent developments in machine learning, along with powerful computational tools, have enabled researchers to develop more sophisticated models to handle such applications using the so-called hybrid generative discriminative models. The main idea is based on exploiting the advantages of both families of models. Thus, the success of such an approach depends on the choice of an appropriate discriminative technique and a suitable generative one. The goal of this paper is to develop a hybrid generative discriminative framework based on support vector machine and Gamma mixture. In particular, we focus on the generation of kernels when examples (images, for instance) are structured data (i.e. described by sets of vectors) modeled by Gamma mixtures. Experimental results on real-world challenging applications, namely 3D shape class recognition, object categorization, and video event analysis, show the effectiveness of the proposed framework.

Data-level fusion is believed to have the potential for enhancing human face recognition. However, due to a number of challenges, current techniques have failed to achieve its full potential. We propose spatially optimized data/pixel-level fusion of 3-D shape and texture for face recognition. Fusion functions are objectively optimized to model expression and illumination variations in linear subspaces for invariant face recognition. Parameters of adjacent functions are constrained to smoothly vary for effective numerical regularization. In addition to spatial optimization, multiple nonlinear fusion models are combined to enhance their learning capabilities. Experiments on the FRGC v2 data set show that spatial optimization, higher order fusion functions, and the combination of multiple such functions systematically improve performance, which is, for the first time, higher than score-level fusion in a similar experimental setup.

We present a novel approach to interest-point detection tailored to range images. A range image is represented by two images with blob-like patterns that have easily detectable peaks and can be efficiently extracted using convolution kernels. These kernels were designed to produce repeatable and independent blob-like patterns when convolved with the range image. The interest-points correspond to peaks of the patterns after dropping the unstable ones and performing Non-Maximal Suppression (NMS) on their union. The approach was applied to facial range images from the FRGC V2.0 dataset and about 88% repeatability was achieved. Face recognition was also performed by matching the local range regions around the interest-points. An approach based on three levels of matching combined with RAN SAC algorithm was used to increase the correct matches and reduce the false ones. Preliminary recognition results for a database of 466 subjects and 1765 probes were 96.33% identification rate and 90% verification rate at 0.1% False Accept Rate (FAR) for faces under neutral expression.