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This paper presents a novel speckle reduction algorithm based on sparse representation and structure characteristics of PolSAR image. First, each pixel in original image is classified into bright point or line targets, dark point or line targets and others to form a classification map. Second, sparse decomposition and reconstruction is performed on PolSAR image by OMP and K-SVD methods to filter speckle...
In current color image super-resolution methods, superresolution based on sparse representation achieves state-of-the-art performance. However, the exploited sparse representation models deal with the color images as independent channel planes. Consequently, these approaches process the color pixels as scalar quantity, lacking of accuracy in describing inter-relationship among color channels. In this...
This paper presents a new method for calculating the low-rank approximation of a highly incomplete trajectory matrix for subspace video stabilization. We extend moving factorization proposed in [1], which is a streamable method based on least squares. By utilizing sparse representation of trajectories, the proposed factorization method is more accurate while still streamable. We test our sparse moving...
Fingerprint-based Audio recognition system must address concurrent objectives. Indeed, fingerprints must be both robust to distortions and discriminative while their dimension must remain to allow fast comparison. This paper proposes to restate these objectives as a penalized sparse representation problem. On top of this dictionary-based approach, we propose a structured sparsity model in the form...
We propose a method for the synthesis of the magnitudes of Head-related Transfer Functions (HRTFs) using a sparse representation of anthropometric features. Our approach treats the HRTF synthesis problem as finding a sparse representation of the subject's anthropometric features w.r.t. the anthropometric features in the training set. The fundamental assumption is that the magnitudes of a given HRTF...
We propose a novel approach to performing change-detection based on sparse representations and dictionary learning. We operate on observations that are finite support signals, which in stationary conditions lie within a union of low dimensional subspaces. We model changes as perturbations of these subspaces and provide an online and sequential monitoring solution to detect them. This approach allows...
Based on the spatial dependence assumption, super-resolution mapping can predict the spatial location of land cover classes within mixed pixels. In this paper, we propose a novel super-resolution mapping method via multi-dictionary based sparse representation, which is robust to noise in both the learning and class allocation process. To better distinguish different classes, the distribution modes...
Acoustic event detection is an important step for audio content analysis and retrieval. Traditional detection techniques model the acoustic events on frame-based spectral features. Considering the temporal-frequency structures of acoustic events may be distributed in time-scales beyond frames, we propose to represent those structures as a bag of spectral patch exemplars. In order to learn the representative...
Matching Pursuit (MP) is a greedy algorithm that iteratively builds a sparse signal representation. This work presents an analysis of MP in the context of audio denoising. By interpreting the algorithm as a simple shrinkage approach, we identify the factors critical to its success, and propose several approaches to improve its performance and robustness. We present experimental results on a wide range...
The estimation of the number of people present in an image has many applications such as intelligent transportation, urban planning and crowd surveillance. Rather than conventional counting by detection or regression/machine-learning methods, we propose an image retrieval approach, which uses an image descriptor to estimate the people count. We review the performance of several image descriptors....
When the iris images for training and testing are acquired by different iris image sensors, the recognition rate will be degraded and not as good as the one when both sets of images are acquired by the same image sensors. Such problem is called “heterogeneous iris recognition”. In this paper, we propose two novel patch-based heterogeneous dictionary learning methods using heterogeneous eigeniris and...
Video representation is an important and challenging task in the computer vision community. In this paper, we assume that image frames of a moving scene can be modeled as a Markov random process. We propose a sparse coding framework, named adaptive video dictionary learning (AVDL), to model a video adaptively. The developed framework is able to capture the dynamics of a moving scene by exploring both...
We present in this paper an exemplar-based voice conversion (VC) method using a phoneme-categorized dictionary. Sparse representation-based VC using Non-negative matrix factorization (NMF) is employed for spectral conversion between different speakers. In our previous NMF-based VC method, source exemplars and target exemplars are extracted from parallel training data, having the same texts uttered...
Many successful image quality metrics rely on the structural information in an image to assess its perceptual quality. Extracting the structural information that is perceptually meaningful to our visual system, however, is a challenging task. This paper proposes a new quality assessment metric that relies on a sparse modeling approach to learn the inherent structures of the image. These structures...
When applying sparse representation techniques to images, the standard approach is to independently compute the representations for a set of overlapping image patches. This method performs very well in a variety of applications, but the independent sparse coding of each patch results in a representation that is not optimal for the image as a whole. A recent development is convolutional sparse coding,...
In this paper, a novel image blocky artifact removal scheme based on low-rank matrix recovery is proposed. The problem of suppressing blocky artifacts is formulated as recovering a low-rank matrix from corrupted observations. During the deblocking processing, we do not directly recover the whole clean image but only its high-frequency component and then synthesize the clean image by incorporating...
Time-varying linear prediction has been studied in the context of speech signals, in which the auto-regressive (AR) coefficients of the system function are modeled as a linear combination of a set of known bases. Traditionally, least squares minimization is used for the estimation of model parameters of the system. Motivated by the sparse nature of the excitation signal for voiced sounds, we explore...
Sparse dictionary learning has attracted enormous interest in image processing and data representation in recent years. To improve the performance of dictionary learning, we propose an efficient block-structured incoherent K-SVD algorithm for the sparse representation of signals. Without relying on any prior knowledge of the group structure for the input data, we develop a two-stage agglomerative...
Recent studies have suggested that the critical aspect of sparse representation-based classification (SRC) is collaborative representation, rather than sparsity. This has given rise to fast collaborative representation-based classification using 2-norm regularized least squares (CRC-RLS). This paper digs deeper into the difference between SRC and CRC-RLS. We show that linear coding schemes such as...
In this paper we consider the dictionary learning problem for sparse representation. We first show that this problem is NP-hard and then propose an efficient dictionary learning scheme to solve several practical formulations of this problem. Unlike many existing algorithms in the literature, such as K-SVD, our proposed dictionary learning scheme is theoretically guaranteed to converge to the set of...
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