When building a performing one-class classifier, the low variance direction of the training data set might provide important information. The low variance direction of the training data set improves the Covariance-guided One-Class Support Vector Machine (COSVM), resulting in better accuracy. However, this classifier does not use data dispersion in the one class. It explicitly does not make use of target class subclass information. As a solution, we propose Scatter Covariance-guided One-Class Support Vector Machine, a novel variation of the COSVM classifier (SC-OSVM). In the kernel space, our approach makes use of subclass information to jointly decrease dispersion. Our algorithm technique is even based on a convex optimization problem that can be efficiently solved using standard numerical methods. A comparison of artificial and real-world data sets shows that SC-OSVM provides more efficient and robust solutions than normal COSVM and other contemporary one-class classifiers.

We introduce a new gesture recognition framework based on learning local motion signatures (LMSs) of HOG descriptors introduced by [1]. Our main contribution is to propose a new probabilistic learning-classification scheme based on a reliable tracking of local features. After the generation of these LMSs computed on one individual by tracking Histograms of Oriented Gradient (HOG) [2] descriptor, we learn a codebook of video-words (i.e., clusters of LMSs) using k-means algorithm on a learning gesture video database. Then, the video-words are compacted to a code-book of codewords by the Maximization of Mutual Information (MMI) algorithm. At the final step, we compare the LMSs generated for a new gesture w.r.t. the learned code-book via the k-nearest neighbors (k-NN) algorithm and a novel voting strategy. Our main contribution is the handling of the N to N mapping between codewords and gesture labels within the proposed voting strategy. Experiments have been carried out on two public gesture databases: KTH [3] and IXMAS [4]. Results show that the proposed method outperforms recent state-of-the-art methods.

This paper overviews a new gesture recognition framework based on learning local motion signatures (LMSs) introduced by [5]. After the generation of these LMSs computed on one individual by tracking Histograms of Oriented Gradient (HOG) [2] descriptor, we learn a codebook of video-words (i.e. clusters of LMSs) using k-means algorithm on a learning gesture video database. Then the video-words are compacted to a codebook of code-words by the Maximization of Mutual Information (MMI) algorithm. At the final step, we compare the LMSs generated for a new gesture w.r.t. the learned codebook via the k-nearest neighbors (k-NN) algorithm and a novel voting strategy. Our main contribution is the handling of the N to N mapping between code-words and gesture labels with the proposed voting strategy. Experiments have been carried out on two public gesture databases: KTH [16] and IXMAS [19]. Results show that the proposed method outperforms recent state-of-the-art methods.

We introduce a new HoG (Histogram of Oriented Gradients) tracker for Gesture Recognition. Our main contribution is to build HoG trajectory descriptors (representing local motion) which are used for gesture recognition. First,we select for each individual in the scene a set of corner points to determine textured regions where to compute 2D HoG descriptors. Second, we track these 2D HoG descriptors in order to build temporal HoG descriptors. Lost descriptors are replaced by newly detected ones. Finally, we extract the local motion descriptors to learn offline a set of given gestures.Then, a new video can be classified according to the gesture occurring in the video. Results shows that the tracker performs well compared to KLT tracker. The generated local motion descriptors are validated through gesture learning-classification using the KTH action database.

This paper describes a method for action recognition using a classification algorithm based on mixtures of von Mises distributions processing action signatures. An action signature is a 1D sequence of angles, forming a trajectory, which are extracted from a 2D map of adjusted orientations (subtracting the average orientation) of the gradient of the motion-history image. To obtain the action signature, the authors scan the image along the direction given by the average gradient orientation, selecting only the points for which the motion energy is equal to 1.