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Rajeev Sharma

Bio: Rajeev Sharma is an academic researcher from Pennsylvania State University. The author has contributed to research in topics: Gesture & Gesture recognition. The author has an hindex of 34, co-authored 107 publications receiving 5446 citations. Previous affiliations of Rajeev Sharma include University of Illinois at Urbana–Champaign.


Papers
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Book ChapterDOI
TL;DR: This paper investigates the use of Support Vector Machines for the purpose of gender classification and finds that the SVM outperformed the other two classifiers on all datasets.
Abstract: Computer vision systems for monitoring people and collecting valuable demographics in a social environment will play an increasingly important role in enhancing user's experience and can significantly improve the intelligibility of a human computer interaction (HCI) system. For example, a robust gender classification system is expected to provide a basis for passive surveillance and access to a smart building using demographic information or can provide valuable consumer statistics in a public place. The option of an audio cue in addition to the visual cue promises a robust solution with high accuracy and ease-of-use in human computer interaction systems.This paper investigates the use of Support Vector Machines(SVMs) for the purpose of gender classification. Both visual (thumbnail frontal face) and audio (features from speech data) cues were considered for designing the classifier and the performance obtained by using each cue was compared. The performance of the SVM was compared with that of two simple classifiers namely, the nearest prototype neighbor and the k-nearest neighbor on all feature sets. It was found that the SVM outperformed the other two classifiers on all datasets. The best overall classification rates obtained using the SVM for the visual and speech data were 95.31% and 100%, respectively.

21 citations

Proceedings ArticleDOI
18 Jun 2003
TL;DR: This paper presents a systematic approach to acquiring model appearance information online for monocular model-based tracking and shows that the presented algorithm is able to robustly track a wide variety of targets under challenging conditions.
Abstract: This paper presents a systematic approach to acquiring model appearance information online for monocular model-based tracking. The acquired information is used to drive a set of complementary imaging cues to obtain a highly discriminatory observation model. Appearance is modeled as a Markov random field of color distributions over the model surface. The online acquisition process estimates appearance-based on uncertain image measurements and is designed to greatly reduce the chance of mapping non-object image data onto the model. Confidences about the different appearance driven imaging cues are estimated in order to adaptively balance the contributions of the different cues. The discriminatory power of the resulting model is good enough to allow long-duration single-hypothesis model-based tracking with no prior appearance information. Careful evaluation based on real and semi-synthetic video sequences shows that the presented algorithm is able to robustly track a wide variety of targets under challenging conditions.

21 citations

Proceedings ArticleDOI
14 Apr 1998
TL;DR: A multimodal localization scheme combined with a tracking framework that exploits the articulated structure of the arm is proposed that uses the multiple cues of motion, shape and color to locate a set of image features.
Abstract: A key problem in building an interface in which the user uses hand gestures to control a computer generated display without restrictions is the ability to localize and track the human arm in image sequences. The paper proposes a multimodal localization scheme combined with a tracking framework that exploits the articulated structure of the arm. The localization uses the multiple cues of motion, shape and color to locate a set of image features. Using constraint fusion, these features are tracked by a modified extended Kalman filter. An interaction scheme between tracking and localization is proposed in order to improve the estimation while decreasing the computational requirement. The results of extensive simulations and experiments with real data are described including a large database of hand gestures involved in display control.

21 citations

Book ChapterDOI
01 Jan 1996
TL;DR: A conceptual framework for multimodal human-computer interaction for manipulating a virtual object and specific techniques are presented for using a combination of speech and gesture for manipulating virtual objects.
Abstract: Although there has been a tremendous progress in recent years in 3-D, immersive display and virtual reality (VR) technologies, the corresponding interface technologies have lagged behind. To fully exploit the potential that VR offers as a means of visualizing and interacting with complex information, it is important to develop “natural” means for interacting with the virtual display. Such natural interaction can be achieved by using an integrated approach where multiple, possibly redundant modes of input such as speech, hand gesture, gaze, and graphical feedback are used simultaneously. This paper presents a conceptual framework for multimodal human-computer interaction for manipulating a virtual object. Specific techniques are presented for using a combination of speech and gesture for manipulating virtual objects. Free hand gestures are analyzed and recognized using computer vision. The gesture analysis is done cooperatively with the speech recognition system and the graphic system. This is demonstrated with the help of an experimental VR setup used by molecular biologists for simulating and visualizing complex molecular structures.

21 citations

Journal ArticleDOI
TL;DR: A robust framework for tracking complex objects in video sequences that exploits the advantages of MHT algorithm which is capable of resolving data association/uncertainty and integrates it with object matching techniques to provide a robust behavior while trackingcomplex objects.

21 citations


Cited by
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Journal ArticleDOI
Ronald Azuma1
TL;DR: The characteristics of augmented reality systems are described, including a detailed discussion of the tradeoffs between optical and video blending approaches, and current efforts to overcome these problems are summarized.
Abstract: This paper surveys the field of augmented reality AR, in which 3D virtual objects are integrated into a 3D real environment in real time. It describes the medical, manufacturing, visualization, path planning, entertainment, and military applications that have been explored. This paper describes the characteristics of augmented reality systems, including a detailed discussion of the tradeoffs between optical and video blending approaches. Registration and sensing errors are two of the biggest problems in building effective augmented reality systems, so this paper summarizes current efforts to overcome these problems. Future directions and areas requiring further research are discussed. This survey provides a starting point for anyone interested in researching or using augmented reality.

8,053 citations

MonographDOI
01 Jan 2006
TL;DR: This coherent and comprehensive book unifies material from several sources, including robotics, control theory, artificial intelligence, and algorithms, into planning under differential constraints that arise when automating the motions of virtually any mechanical system.
Abstract: Planning algorithms are impacting technical disciplines and industries around the world, including robotics, computer-aided design, manufacturing, computer graphics, aerospace applications, drug design, and protein folding. This coherent and comprehensive book unifies material from several sources, including robotics, control theory, artificial intelligence, and algorithms. The treatment is centered on robot motion planning but integrates material on planning in discrete spaces. A major part of the book is devoted to planning under uncertainty, including decision theory, Markov decision processes, and information spaces, which are the “configuration spaces” of all sensor-based planning problems. The last part of the book delves into planning under differential constraints that arise when automating the motions of virtually any mechanical system. Developed from courses taught by the author, the book is intended for students, engineers, and researchers in robotics, artificial intelligence, and control theory as well as computer graphics, algorithms, and computational biology.

6,340 citations

Journal ArticleDOI
01 Oct 1996
TL;DR: This article provides a tutorial introduction to visual servo control of robotic manipulators by reviewing the prerequisite topics from robotics and computer vision, including a brief review of coordinate transformations, velocity representation, and a description of the geometric aspects of the image formation process.
Abstract: This article provides a tutorial introduction to visual servo control of robotic manipulators. Since the topic spans many disciplines our goal is limited to providing a basic conceptual framework. We begin by reviewing the prerequisite topics from robotics and computer vision, including a brief review of coordinate transformations, velocity representation, and a description of the geometric aspects of the image formation process. We then present a taxonomy of visual servo control systems. The two major classes of systems, position-based and image-based systems, are then discussed in detail. Since any visual servo system must be capable of tracking image features in a sequence of images, we also include an overview of feature-based and correlation-based methods for tracking. We conclude the tutorial with a number of observations on the current directions of the research field of visual servo control.

3,619 citations

Book
01 Jan 2006
TL;DR: In this paper, the Jacobian is used to describe the relationship between rigid motions and homogeneous transformations, and a linear algebraic approach is proposed for vision-based control of dynamical systems.
Abstract: Preface. 1. Introduction. 2. Rigid Motions and Homogeneous Transformations. 3. Forward and Inverse Kinematics. 4. Velocity Kinematics-The Jacobian. 5. Path and Trajectory Planning. 6. Independent Joint Control. 7. Dynamics. 8. Multivariable Control. 9. Force Control. 10. Geometric Nonlinear Control. 11. Computer Vision. 12. Vision-Based Control. Appendix A: Trigonometry. Appendix B: Linear Algebra. Appendix C: Dynamical Systems. Appendix D: Lyapunov Stability. Index.

3,100 citations

Journal ArticleDOI
TL;DR: The context for socially interactive robots is discussed, emphasizing the relationship to other research fields and the different forms of “social robots”, and a taxonomy of design methods and system components used to build socially interactive Robots is presented.

2,869 citations