Namrata Vaswani is an Indian-American electrical engineer known for her research in compressed sensing, robust principal component analysis, signal processing, statistical learning theory, and computer vision. [1] She is a Joseph and Elizabeth Anderlik Professor in Electrical and Computer Engineering at Iowa State University, and (by courtesy) a professor of mathematics at Iowa State. [2]
Namrata Vaswani earned a bachelor's degree in electrical engineering at the Indian Institute of Technology Delhi in 1999. She completed a Ph.D. in electrical and computer engineering in 2004 at the University of Maryland, College Park. [2] Her doctoral advisor was Rama Chellappa, [3] and her dissertation was Change detection in stochastic shape dynamical models with applications in activity modeling and abnormality detection. [4]
After postdoctoral research at the Georgia Institute of Technology, she joined the Iowa State faculty in 2005. She was given her courtesy appointment in mathematics in 2013, [2] and the Anderlik Professorship in 2019. [2] [5] She also chairs the Women in Signal Processing Committee of the IEEE Signal Processing Society. [1]
In 2018, Namrata Vaswani was named a Fellow of the IEEE "for contributions to dynamic structured high-dimensional data recovery". [6] . In 2019 she was named a distinguished alumni of the University of Maryland Electrical and Computer Engineering Department. [1]
First, Namrata Vaswani was the first author who developed a dynamic RPCA method [7] in the L+S decomposition framework in 2010 just after the work of Candès et al. [8] in 2009 on RPCA via decomposition into low-rank and sparse matrices. She immediately understood the interest to develop a provable solution to the dynamic RPCA problem, and provided a usable dynamic RPCA method for real-time computer vision applications. Practically, she was a precursor and a pionner in this kind of dynamic RPCA methods.
Second, Namrata Vaswani progressively improved over the years the original ReProCS by addressing both its performance guarantees and its memory efficiency. [9] [10] [11] The last version of ReProCS called PracReProCS is the top method on the large-scale dataset CDnet 2014 (which is a reference in the field of change detection) in the category of dynamic RPCA methods provided with performance guarantees. [12] In 2018, Prof. Namrata Vaswani designed MEROP [13] which is a fast and memory-efficient algorithm for RPCA. In addition, the code of PracReProCS and MEROP is publicly available for the scientific community. By this way, she shows her interest for a sharable and reproducible research.
Third, Namrata Vaswani provided the first valuable unified synthesis/review on dynamic RPCA/subspace tracking algorithms in a mature paper, [14] and she is also a GE of two special issues [15] [16] in RPCA/dynamic RPCA via L+S decomposition showing by these activities her international leadership in this field. In addition, she also provided a very valuable invited talk at the workshop RSL-CV 2017 in conjunction with ICCV 2017 as well as many invited talks in seminars and an invited short-course at IIIT-Delhi showing her investment to diffuse as well as possible her research. She received the IEEE Signal Processing Society (SPS) Best Paper Award in 2014 for her paper on dynamic compressive sensing.
Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are a sequence of numbers that represent samples of a continuous variable in a domain such as time, space, or frequency. In digital electronics, a digital signal is represented as a pulse train, which is typically generated by the switching of a transistor.
Vector quantization (VQ) is a classical quantization technique from signal processing that allows the modeling of probability density functions by the distribution of prototype vectors. Developed in the early 1980s by Robert M. Gray, it was originally used for data compression. It works by dividing a large set of points (vectors) into groups having approximately the same number of points closest to them. Each group is represented by its centroid point, as in k-means and some other clustering algorithms. In simpler terms, vector quantization chooses a set of points to represent a larger set of points.
Principal component analysis (PCA) is a linear dimensionality reduction technique with applications in exploratory data analysis, visualization and data preprocessing.
In signal processing, direction of arrival (DOA) denotes the direction from which usually a propagating wave arrives at a point, where usually a set of sensors are located. These set of sensors forms what is called a sensor array. Often there is the associated technique of beamforming which is estimating the signal from a given direction. Various engineering problems addressed in the associated literature are:
In electrical engineering and applied mathematics, blind deconvolution is deconvolution without explicit knowledge of the impulse response function used in the convolution. This is usually achieved by making appropriate assumptions of the input to estimate the impulse response by analyzing the output. Blind deconvolution is not solvable without making assumptions on input and impulse response. Most of the algorithms to solve this problem are based on assumption that both input and impulse response live in respective known subspaces. However, blind deconvolution remains a very challenging non-convex optimization problem even with this assumption.
Non-negative matrix factorization, also non-negative matrix approximation is a group of algorithms in multivariate analysis and linear algebra where a matrix V is factorized into (usually) two matrices W and H, with the property that all three matrices have no negative elements. This non-negativity makes the resulting matrices easier to inspect. Also, in applications such as processing of audio spectrograms or muscular activity, non-negativity is inherent to the data being considered. Since the problem is not exactly solvable in general, it is commonly approximated numerically.
Matching pursuit (MP) is a sparse approximation algorithm which finds the "best matching" projections of multidimensional data onto the span of an over-complete dictionary . The basic idea is to approximately represent a signal from Hilbert space as a weighted sum of finitely many functions taken from . An approximation with atoms has the form
An autoencoder is a type of artificial neural network used to learn efficient codings of unlabeled data. An autoencoder learns two functions: an encoding function that transforms the input data, and a decoding function that recreates the input data from the encoded representation. The autoencoder learns an efficient representation (encoding) for a set of data, typically for dimensionality reduction.
MUSIC is an algorithm used for frequency estimation and radio direction finding.
Compressed sensing is a signal processing technique for efficiently acquiring and reconstructing a signal, by finding solutions to underdetermined linear systems. This is based on the principle that, through optimization, the sparsity of a signal can be exploited to recover it from far fewer samples than required by the Nyquist–Shannon sampling theorem. There are two conditions under which recovery is possible. The first one is sparsity, which requires the signal to be sparse in some domain. The second one is incoherence, which is applied through the isometric property, which is sufficient for sparse signals. Compressed sensing has applications in, for example, MRI where the incoherence condition is typically satisfied.
Ali Naci Akansu is a Turkish-American professor of electrical & computer engineering and scientist in applied mathematics.
In statistical signal processing, the goal of spectral density estimation (SDE) or simply spectral estimation is to estimate the spectral density of a signal from a sequence of time samples of the signal. Intuitively speaking, the spectral density characterizes the frequency content of the signal. One purpose of estimating the spectral density is to detect any periodicities in the data, by observing peaks at the frequencies corresponding to these periodicities.
Foreground detection is one of the major tasks in the field of computer vision and image processing whose aim is to detect changes in image sequences. Background subtraction is any technique which allows an image's foreground to be extracted for further processing.
In communications technology, the technique of compressed sensing (CS) may be applied to the processing of speech signals under certain conditions. In particular, CS can be used to reconstruct a sparse vector from a smaller number of measurements, provided the signal can be represented in sparse domain. "Sparse domain" refers to a domain in which only a few measurements have non-zero values.
Robust Principal Component Analysis (RPCA) is a modification of the widely used statistical procedure of principal component analysis (PCA) which works well with respect to grossly corrupted observations. A number of different approaches exist for Robust PCA, including an idealized version of Robust PCA, which aims to recover a low-rank matrix L0 from highly corrupted measurements M = L0 +S0. This decomposition in low-rank and sparse matrices can be achieved by techniques such as Principal Component Pursuit method (PCP), Stable PCP, Quantized PCP, Block based PCP, and Local PCP. Then, optimization methods are used such as the Augmented Lagrange Multiplier Method (ALM), Alternating Direction Method (ADM), Fast Alternating Minimization (FAM), Iteratively Reweighted Least Squares (IRLS ) or alternating projections (AP).
In computer vision, rigid motion segmentation is the process of separating regions, features, or trajectories from a video sequence into coherent subsets of space and time. These subsets correspond to independent rigidly moving objects in the scene. The goal of this segmentation is to differentiate and extract the meaningful rigid motion from the background and analyze it. Image segmentation techniques labels the pixels to be a part of pixels with certain characteristics at a particular time. Here, the pixels are segmented depending on its relative movement over a period of time i.e. the time of the video sequence.
Sparse dictionary learning is a representation learning method which aims at finding a sparse representation of the input data in the form of a linear combination of basic elements as well as those basic elements themselves. These elements are called atoms and they compose a dictionary. Atoms in the dictionary are not required to be orthogonal, and they may be an over-complete spanning set. This problem setup also allows the dimensionality of the signals being represented to be higher than the one of the signals being observed. The above two properties lead to having seemingly redundant atoms that allow multiple representations of the same signal but also provide an improvement in sparsity and flexibility of the representation.
René Vidal is a Chilean electrical engineer and computer scientist who is known for his research in machine learning, computer vision, medical image computing, robotics, and control theory. He is the Herschel L. Seder Professor of the Johns Hopkins Department of Biomedical Engineering, and the founding director of the Mathematical Institute for Data Science (MINDS).
L1-norm principal component analysis (L1-PCA) is a general method for multivariate data analysis. L1-PCA is often preferred over standard L2-norm principal component analysis (PCA) when the analyzed data may contain outliers.
Video super-resolution (VSR) is the process of generating high-resolution video frames from the given low-resolution video frames. Unlike single-image super-resolution (SISR), the main goal is not only to restore more fine details while saving coarse ones, but also to preserve motion consistency.