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Brain tumor segmentation, an essential but challenging task, has long attracted much attention from the medical imaging community. Recently, successful applications of sparse coding and dictionary learning has emerged in various vision problems including image segmentation. In this paper, a superpixel-based framework for automated brain tumor segmentation is introduced. The kernel trick is adopted...
Often, videos are composed of multiple concepts or even genres. For instance, news videos may contain sports, action, nature, etc. Therefore, encoding the distribution of such concepts/genres in a compact and effective representation is a challenging task. In this sense, we propose the Bag of Genres representation, which is based on a visual dictionary defined by a genre classifier. Each visual word...
In this paper, we present a novel scheme for text-independent online writer identification. As a first contribution, we propose histogram based features, inspired from the area of object detection, to describe the structural primitives of handwriting. Secondly, we have used sparse coding techniques to learn prototypes, that describe the general writing characteristics of the authors. To the best of...
The kernel trick becomes a burden for some machine learning tasks such as dictionary learning, where a huge amount of training samples are needed, making the kernel matrix gigantic and infeasible to store or process. In this work, we propose to alleviate this problem and achieve Gaussian RBF kernel expansion explicitly for dictionary learning using Fastfood transform, which is an approximation of...
The growing demand for smarter high-performance embedded systems leads to the integration of multiple functionalities in on-chip systems with tens (even hundreds) of cores. This trend opens a very challenging question about the optimal resource allocation in those manycore systems. Answering this question is key to meet the performance and energy requirements. This paper deals with a learning technique...
We consider the problem of learning graphs in a sparse multiclass support vector machines framework. For such a problem, sparse graph penalty is useful to select the significant features and interpret the results. Classical ℓ1-norm learns a sparse solution without considering the structure between the features. In this paper, a structural knowledge is encoded as directed acyclic graph and a graph...
In recent years, mass atrocities, terrorism, and political unrest have caused much human suffering. Thousands of innocent lives have been lost to these events. With the help of advanced technologies, we can now dream of a tool that uses machine learning and natural language processing (NLP) techniques to warn of such events. Detecting atrocities demands structured event data that contain metadata,...
We introduce and analyse a flexible and efficient implementation of Bayesian dictionary learning for sparse coding. By placing Gaussian-inverse-Gamma hierarchical priors on the coefficients, the model can automatically determine the required sparsity level for good reconstructions, whilst also automatically learning the noise level in the data, obviating the need for heuristic methods for choosing...
We present TACCLE3 — Coding European Project (Ref. 2015-1-BE02-KA201-012307) in the XVIII International Symposium on Computers and Education — SIIE 2016, held within the V Congreso Nacional de Informática — CEDI 2016 in the University of Salamanca, Spain, September 14th–16th, 2016. One of the sessions was devoted to Computational Thinking topic and TACCLE3 was selected to open this session. Taccle3...
As an unsupervised learning method, sparse coding can discover high-level representations for an input in a large variety of learning problems. Under semi-supervised settings, sparse coding is used to extract features for a supervised task such as classification. While sparse representations learned from unlabeled data independently of the supervised task perform well, we argue that sparse coding...
Facial point detection in real-world conditions presents large variations in shapes and occlusions due to differences in poses, expressions, use of accessories, which may lead to a large difficultly in locating facial points. In this paper, we propose a regression-based sparse coding method for facial point detection. The method combines the regression-based concept with sparse reconstruction methods...
A hallmark of biological systems is their ability to self-calibrate sensory-motor loops during their development. Understanding the principles of such self-calibration will enable the design of robots with similar autonomous learning abilities. Here we consider the problem of active depth perception based on motion parallax. When an observer moves sideways while looking at an object with a single...
This method introduces an efficient manner of learning action categories without the need of feature estimation. The approach starts from low-level values, in a similar style to the successful CNN methods. However, rather than extracting general image features, we learn to predict specific video representations from raw video data. The benefit of such an approach is that at the same computational...
A discriminative dictionary learning algorithm is proposed to find sparse signal representations using relative attributes as the available semantic information. In contrast, existing (discriminative) dictionary learning (DDL) approaches mostly utilize binary label information to enhance the discriminative property of the signal reconstruction residual, the sparse coding vectors or both. Compared...
Deep Convolutional Neural Networks (CNN) have recently been shown to outperform previous state of the art approaches for image classification. Their success must in parts be attributed to the availability of large labeled training sets such as provided by the ImageNet benchmarking initiative. When training data is scarce, however, CNNs have proven to fail to learn descriptive features. Recent research...
Visual question answering (VQA) comes as a result of great development in computer vision and natural language processing, which requires deep understanding of images and questions and effective integration of them. Current works on VQA simply concatenated visual and textual features or compared them via dot product, which were unable to eliminate the semantic difference between them. We argue to...
We propose a novel computationally efficient hierarchical dictionary learning (HDL) approach for data-driven unmixing and functional connectivity analysis of functional magnetic resonance imaging (fMRI) data. It is shown that by simultaneously exploiting the sparsity of the spatial brain maps and the incoherence among their evolution in time or task functions, one can achieve better performance while...
Position-patch based face hallucination approaches have been proposed to replace the probabilistic graph-based or manifold learning-based models recently. In this paper, we propose a novel position-based face hallucination method based on locality-constrained matrix regression (LcMR). LcMR uses nuclear norm to characterize the reconstruction error straightforward, thus preserving the essential structural...
Despite the fact that different objects possess distinct class-specific features, they also usually share common patterns. Inspired by this observation, we propose a novel method to explicitly and simultaneously learn a set of common patterns as well as class-specific features for classification. Our dictionary learning framework is hence characterized by both a shared dictionary and particular (class-specific)...
With the advance of 3-dimensional sensing devices, the in-air handwriting, as a more natural way for human and computer interaction, is being developed by the UCAS-CVMT Lab. Compared with the conventional handwritten Chinese characters generated by touching, it is more challenging to accurately recognize them due to unconstrained one-stroke writing style. This paper presents two recognizers to address...
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