@article {13333, title = {Supercubes: A High-Level Primitive for Diamond Hierarchies}, journal = {Visualization and Computer Graphics, IEEE Transactions on}, volume = {15}, year = {2009}, month = {2009///}, pages = {1603 - 1610}, abstract = {Volumetric datasets are often modeled using a multiresolution approach based on a nested decomposition of the domain into a polyhedral mesh. Nested tetrahedral meshes generated through the longest edge bisection rule are commonly used to decompose regular volumetric datasets since they produce highly adaptive crack-free representations. Efficient representations for such models have been achieved by clustering the set of tetrahedra sharing a common longest edge into a structure called a diamond. The alignment and orientation of the longest edge can be used to implicitly determine the geometry of a diamond and its relations to the other diamonds within the hierarchy. We introduce the supercube as a high-level primitive within such meshes that encompasses all unique types of diamonds. A supercube is a coherent set of edges corresponding to three consecutive levels of subdivision. Diamonds are uniquely characterized by the longest edge of the tetrahedra forming them and are clustered in supercubes through the association of the longest edge of a diamond with a unique edge in a supercube. Supercubes are thus a compact and highly efficient means of associating information with a subset of the vertices, edges and tetrahedra of the meshes generated through longest edge bisection. We demonstrate the effectiveness of the supercube representation when encoding multiresolution diamond hierarchies built on a subset of the points of a regular grid. We also show how supercubes can be used to efficiently extract meshes from diamond hierarchies and to reduce the storage requirements of such variable-resolution meshes.}, keywords = {(computer, adaptive, approach;nested, bisection, crack-free, datasets;computational, decomposition;nested, diamond, generation;rendering, geometry;mesh, graphics);, hierarchies;edge, mesh;supercubes;tetrahedra, meshes;polyhedral, representations;multiresolution, rule;highly, sharing;volumetric, tetrahedral}, isbn = {1077-2626}, doi = {10.1109/TVCG.2009.186}, author = {Weiss,K. and De Floriani, Leila} } @article {18161, title = {Adaptive Detection for Group-Based Multimedia Fingerprinting}, journal = {Signal Processing Letters, IEEE}, volume = {14}, year = {2007}, month = {2007/12//}, pages = {964 - 967}, abstract = {Grouping strategy has been proposed recently to leverage the prior knowledge on collusion pattern to improve collusion resistance in multimedia fingerprinting. However, the improvement is not consistent, as reduced performance of the existing group-based fingerprinting schemes than the non-grouped ones is observed when the grouping does not match the true collusion pattern well. In this letter, we propose a new adaptive detection method, where the threshold for the group detection can be adjusted automatically according to the detection statistics that reflect the underlying collusion pattern. Experimental results show that the proposed adaptive detection outperforms nonadaptive detection and provides consistent performance improvement over non-grouped orthogonal fingerprinting schemes under various collusion scenarios.}, keywords = {adaptive, computing;security, data;, detection;collusion, detection;group-based, fingerprinting;copy, fingerprinting;grouping, multimedia, of, orthogonal, pattern;detection, protection;multimedia, statistics;group, strategy;nongrouped}, isbn = {1070-9908}, doi = {10.1109/LSP.2007.907992}, author = {He,Shan and M. Wu} } @article {13995, title = {Flexible and Optimal Design of Spherical Microphone Arrays for Beamforming}, journal = {Audio, Speech, and Language Processing, IEEE Transactions on}, volume = {15}, year = {2007}, month = {2007/02//}, pages = {702 - 714}, abstract = {This paper describes a methodology for designing a flexible and optimal spherical microphone array for beamforming. Using the approach presented, a spherical microphone array can have very flexible layouts of microphones on the spherical surface, yet optimally approximate a desired beampattern of higher order within a specified robustness constraint. Depending on the specified beampattern order, our approach automatically achieves optimal performances in two cases: when the specified beampattern order is reachable within the robustness constraint we achieve a beamformer with optimal approximation of the desired beampattern; otherwise we achieve a beamformer with maximum directivity, both robustly. For efficient implementation, we also developed an adaptive algorithm for computing the beamformer weights. It converges to the optimal performance quickly while exactly satisfying the specified frequency response and robustness constraint in each step. One application of the method is to allow the building of a real-world system, where microphones may not be placeable on regions, such as near cable outlets and/or a mounting base, while having a minimal effect on the performance. Simulation results are presented}, keywords = {adaptive, algorithm;beamforming;beampattern;frequency, arrays;, arrays;acoustic, directivity;optimal, microphone, processing;array, processing;microphone, response;maximum, signal, spherical}, isbn = {1558-7916}, doi = {10.1109/TASL.2006.876764}, author = {Li,Z. and Duraiswami, Ramani} } @conference {13140, title = {Probabilistic Fusion Tracking Using Mixture Kernel-Based Bayesian Filtering}, booktitle = {Computer Vision, 2007. ICCV 2007. IEEE 11th International Conference on}, year = {2007}, month = {2007/10//}, pages = {1 - 8}, abstract = {Even though sensor fusion techniques based on particle filters have been applied to object tracking, their implementations have been limited to combining measurements from multiple sensors by the simple product of individual likelihoods. Therefore, the number of observations is increased as many times as the number of sensors, and the combined observation may become unreliable through blind integration of sensor observations - especially if some sensors are too noisy and non-discriminative. We describe a methodology to model interactions between multiple sensors and to estimate the current state by using a mixture of Bayesian filters - one filter for each sensor, where each filter makes a different level of contribution to estimate the combined posterior in a reliable manner. In this framework, an adaptive particle arrangement system is constructed in which each particle is allocated to only one of the sensors for observation and a different number of samples is assigned to each sensor using prior distribution and partial observations. We apply this technique to visual tracking in logical and physical sensor fusion frameworks, and demonstrate its effectiveness through tracking results.}, keywords = {(numerical, adaptive, arrangement, Bayesian, Filtering, filtering;multiple, filters;probabilistic, fusion, fusion;tracking;, integration;mixture, kernel-based, methods);sensor, methods;array, particle, processing;particle, sensors;object, signal, system;blind, techniques;visual, tracking;Bayes, tracking;particle, tracking;sensor}, doi = {10.1109/ICCV.2007.4408938}, author = {Han,Bohyung and Joo,Seong-Wook and Davis, Larry S.} } @article {12587, title = {Target Tracking Using a Joint Acoustic Video System}, journal = {Multimedia, IEEE Transactions on}, volume = {9}, year = {2007}, month = {2007/06//}, pages = {715 - 727}, abstract = {In this paper, a multitarget tracking system for collocated video and acoustic sensors is presented. We formulate the tracking problem using a particle filter based on a state-space approach. We first discuss the acoustic state-space formulation whose observations use a sliding window of direction-of-arrival estimates. We then present the video state space that tracks a target{\textquoteright}s position on the image plane based on online adaptive appearance models. For the joint operation of the filter, we combine the state vectors of the individual modalities and also introduce a time-delay variable to handle the acoustic-video data synchronization issue, caused by acoustic propagation delays. A novel particle filter proposal strategy for joint state-space tracking is introduced, which places the random support of the joint filter where the final posterior is likely to lie. By using the Kullback-Leibler divergence measure, it is shown that the joint operation of the filter decreases the worst case divergence of the individual modalities. The resulting joint tracking filter is quite robust against video and acoustic occlusions due to our proposal strategy. Computer simulations are presented with synthetic and field data to demonstrate the filter{\textquoteright}s performance}, keywords = {(numerical, acoustic, adaptive, appearance, approach;synchronization;time-delay, data, delay;acoustic, divergence;acoustic, estimate;joint, estimation;hidden, feature, filter;sliding, Filtering, fusion;multitarget, fusion;synchronisation;target, highways;direction-of-arrival, Kullback-Leibler, methods);sensor, model;particle, processing;, processing;automated, propagation, removal;optical, signal, system;multimodal, tracking;acoustic, tracking;direction-of-arrival, tracking;occlusion;online, tracking;particle, tracking;video, variable;visual, video, window;state-space}, isbn = {1520-9210}, doi = {10.1109/TMM.2007.893340}, author = {Cevher, V. and Sankaranarayanan,A. C and McClellan, J.H. and Chellapa, Rama} } @conference {12617, title = {An Adaptive Threshold Method for Hyperspectral Target Detection}, booktitle = {Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on}, volume = {5}, year = {2006}, month = {2006/05//}, pages = {V - V}, abstract = {In this paper, we present a new approach to automatically determine a detector threshold. This research problem is especially important in hyperspectral target detection as targets are typically very similar to the background. While a number of methods exist to determine the threshold, these methods require either large amounts of data or make simplifying assumptions about the background distribution. We use a method called inverse blind importance sampling which requires few samples and makes no a-priori assumptions about the background statistics. Results show the promise of this algorithm to determine thresholds for fixed false alarm densities in hyperspectral detectors}, keywords = {adaptive, blind, detection;, detection;inverse, importance, method;background, processing;importance, sampling;geophysical, sampling;object, signal, statistics;hyperspectral, target, threshold}, doi = {10.1109/ICASSP.2006.1661497}, author = {Broadwater, J. and Chellapa, Rama} } @conference {18279, title = {Security Issues in Cooperative Communications: Tracing Adversarial Relays}, booktitle = {Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on}, volume = {4}, year = {2006}, month = {2006/05//}, pages = {IV - IV}, abstract = {Cooperative communication system explores a new dimension of diversity in wireless communications to combat unfriendly wireless environment through strategic relays. While this emerging technology is promising in improving communication quality, some security problems inherent to cooperative relay also arise. In this paper we investigate the security issues in cooperative communications that consist of multiple relay nodes using decode-and-forward strategy. In particular, we consider the situation where one of the relay nodes is adversarial and tries to corrupt the communications by sending garbled signals. We show that the conventional physical-layer signal detection will not be effective in such a scenario, and the application-layer cryptography alone is not sufficient to identify the adversarial relay. To combat adversarial relay, we propose a cross-layer scheme that uses pseudo-random tracing symbols, with an adaptive signal detection rule at the physical layer, and direct sequence spread spectrum symbol construction at the application layer for tracing and identifying adversarial relay. Our experimental simulations show that the proposed tracing scheme is effective and efficient}, keywords = {adaptive, Communication, communications;adaptive, construction;multiple, detection;adversarial, detection;decoding;radiocommunication;telecommunication, issues;strategic, nodes;pseudo-random, relay, relay;decode-and-forward, relays;cooperative, relays;wireless, security;, sequence, signal, spectrum, spread, strategy;direct, symbol, symbols;security, system;cooperative, tracing}, doi = {10.1109/ICASSP.2006.1660907}, author = {Mao,Yinian and M. Wu} } @conference {13193, title = {Robust observations for object tracking}, booktitle = {Image Processing, 2005. ICIP 2005. IEEE International Conference on}, volume = {2}, year = {2005}, month = {2005/09//}, pages = {II - 442-5 - II - 442-5}, abstract = {It is a difficult task to find an observation model that will perform well for long-term visual tracking. In this paper, we propose an adaptive observation enhancement technique based on likelihood images, which are derived from multiple visual features. The most discriminative likelihood image is extracted by principal component analysis (PCA) and incrementally updated frame by frame to reduce temporal tracking error. In the particle filter framework, the feasibility of each sample is computed using this most discriminative likelihood image before the observation process. Integral image is employed for efficient computation of the feasibility of each sample. We illustrate how our enhancement technique contributes to more robust observations through demonstrations.}, keywords = {(numerical, adaptive, analysis;, component, enhancement;, filter, Filtering, framework;, image, images;, likelihood, methods);, object, observation, particle, PCA;, principal, tracking;}, doi = {10.1109/ICIP.2005.1530087}, author = {Han,Bohyung and Davis, Larry S.} } @conference {12706, title = {3D model refinement using surface-parallax}, booktitle = {Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP {\textquoteright}04). IEEE International Conference on}, volume = {3}, year = {2004}, month = {2004/05//}, pages = {iii - 285-8 vol.3 - iii - 285-8 vol.3}, abstract = {We present an approach to update and refine coarse 3D models of urban environments from a sequence of intensity images using surface parallax. This generalizes the plane-parallax recovery methods to surface-parallax using arbitrary surfaces. A coarse and potentially incomplete depth map of the scene obtained from a digital elevation map (DEM) is used as a reference surface which is refined and updated using this approach. The reference depth map is used to estimate the camera motion and the motion of the 3D points on the reference surface is compensated. The resulting parallax, which is an epipolar field, is estimated using an adaptive windowing technique and used to obtain the refined depth map.}, keywords = {3D, adaptive, arbitrary, camera, coarse, compensation;, Computer, DEM;, depth, digital, ELEVATION, environments;, epipolar, estimation;, field;, image, incomplete, INTENSITY, map;, model, MOTION, parallax;, plane-parallax, reconstruction;, recovery;, refinement;, sequence;, sequences;, surface, surfaces;, urban, vision;, windowing;}, doi = {10.1109/ICASSP.2004.1326537}, author = {Agrawala, Ashok K. and Chellapa, Rama} } @conference {12296, title = {Adaptive replication in peer-to-peer systems}, booktitle = {Distributed Computing Systems, 2004. Proceedings. 24th International Conference on}, year = {2004}, month = {2004///}, pages = {360 - 369}, abstract = {Peer-to-peer systems can be used to form a low-latency decentralized data delivery system. Structured peer-to-peer systems provide both low latency and excellent load balance with uniform query and data distributions. Under the more common skewed access distributions, however, individual nodes are easily overloaded, resulting in poor global performance and lost messages. This paper describes a lightweight, adaptive, and system-neutral replication protocol, called LAR, that maintains low access latencies and good load balance even under highly skewed demand. We apply LAR to Chord and show that it has lower overhead and better performance than existing replication strategies.}, keywords = {adaptive, allocation;, data, databases;, decentralized, delivery, distributed, LAR, low-latency, peer-to-peer, processing;, protocol;, replicated, replication, resource, strategies;, structured, system-neutral, system;, systems;}, doi = {10.1109/ICDCS.2004.1281601}, author = {Gopalakrishnan,V. and Silaghi,B. and Bhattacharjee, Bobby and Keleher,P.} } @conference {12703, title = {Appearance-based tracking and recognition using the 3D trilinear tensor}, booktitle = {Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP {\textquoteright}04). IEEE International Conference on}, volume = {3}, year = {2004}, month = {2004/05//}, pages = {iii - 613-16 vol.3 - iii - 613-16 vol.3}, abstract = {The paper presents an appearance-based adaptive algorithm for simultaneous tracking and recognition by generalizing the transformation model to 3D perspective transformation. A trilinear tensor operator is used to represent the 3D geometrical structure. The tensor is estimated by predicting the corresponding points using the existing affine-transformation based algorithm. The estimated tensor is used to synthesize novel views to update the appearance templates. Some experimental results using airborne video are presented.}, keywords = {3D, adaptive, affine-transformation, airborne, algorithm;, appearance, appearance-based, based, estimation;, geometrical, image, mathematical, novel, object, operator;, operators;, perspective, prediction;, processing;, recognition;, representation;, signal, structure, synthesis;, template, tensor, tensor;, tensors;, tracking;, transformation;, trilinear, updating;, video, video-based, video;, view}, doi = {10.1109/ICASSP.2004.1326619}, author = {Jie Shao and Zhou,S. K and Chellapa, Rama} } @conference {13281, title = {Constant-time navigation in four-dimensional nested simplicial meshes}, booktitle = {Shape Modeling Applications, 2004. Proceedings}, year = {2004}, month = {2004/06//}, pages = {221 - 230}, abstract = {We consider a recursive decomposition of a four-dimensional hypercube into a hierarchy of nested 4-dimensional simplexes, that we call pentatopes. The paper presents an algorithm for finding the neighbors of a pentatope along its five tetrahedral faces in constant time. To this aim, we develop a labeling technique for nested pentatopes that enables their identification by using location codes. The constant-time behavior is achieved through bit manipulation operations, thus avoiding traversing the simplicial hierarchy via pointer following. We discuss an application of this representation to multi-resolution representations of four-dimensional scalar fields. Extracting adaptive continuous approximations of the scalar field from such a model requires generating conforming meshes, i.e., meshes in which the pentatopes match along their tetrahedral faces. Our neighbor finding algorithm enables computing face-adjacent pentatopes efficiently.}, keywords = {4-dimensional, adaptive, algorithm;, approximations;, bit, codes;, computational, constant-time, continuous, decomposition;, face-adjacent, faces;, fields;, finding, following;, four-dimensional, generation;, geometry;, hierarchy;, hypercube;, location, manipulation, mesh, meshes;, multiresolution, navigation;, neighbor, nested, operations;, pentatopes;, pointer, recursive, representation;, scalar, simplexes;, simplicial, tetrahedral}, doi = {10.1109/SMI.2004.1314509}, author = {Lee,M. and De Floriani, Leila and Samet, Hanan} } @conference {12287, title = {Hierarchical routing with soft-state replicas in TerraDir}, booktitle = {Parallel and Distributed Processing Symposium, 2004. Proceedings. 18th International}, year = {2004}, month = {2004/04//}, pages = {48 - 48}, abstract = {Summary form only given. Recent work on peer-to-peer systems has demonstrated the ability to deliver low latencies and good load balance when demand for data is relatively uniform. We describe an adaptive replication protocol that delivers low latencies, good load balance even when demand is heavily skewed. The protocol can withstand arbitrary and instantaneous changes in demand distribution. Our approach also addresses classical concerns related to topological constraints of asymmetrical namespaces, such as hierarchical bottlenecks in the context of hierarchical namespaces. The protocol replicates routing state in an ad-hoc manner based on profiled information, is lightweight, scalable, and requires no replica consistency guarantees.}, keywords = {ad-hoc, adaptive, allocation;, asymmetrical, balancing;, bottlenecks;, consistency, constraints;, delivering;, demand, distribution;, guarantees;, hierarchical, latency, load, low, namespaces;, peer-to-peer, protocol;, protocols;, replica, replicas;, replication, resource, routing;, soft-state, systems;, TerraDir;, topological}, doi = {10.1109/IPDPS.2004.1302967}, author = {Silaghi,B. and Gopalakrishnan,Vijay and Bhattacharjee, Bobby and Kelcher,P.} } @conference {13214, title = {Object tracking by adaptive feature extraction}, booktitle = {Image Processing, 2004. ICIP {\textquoteright}04. 2004 International Conference on}, volume = {3}, year = {2004}, month = {2004/10//}, pages = {1501 - 1504 Vol. 3 - 1501 - 1504 Vol. 3}, abstract = {Tracking objects in the high-dimensional feature space is not only computationally expensive but also functionally inefficient. Selecting a low-dimensional discriminative feature set is a critical step to improve tracker performance. A good feature set for tracking can differ from frame to frame due to the changes in the background against the tracked object, and due to an on-line algorithm that adaptively determines a advantageous distinctive feature set. In this paper, multiple heterogeneous features are assembled, and likelihood images are constructed for various subspaces of the combined feature space. Then, the most discriminative feature is extracted by principal component analysis (PCA) based on those likelihood images. This idea is applied to the mean-shift tracking algorithm [D. Comaniciu et al., June 2000], and we demonstrate its effectiveness through various experiments.}, keywords = {adaptive, algorithm;, analysis;, colour, component, extraction;, feature, feature;, heterogeneous, image, image;, likelihood, Mean-shift, object, online, principal, tracking, tracking;}, doi = {10.1109/ICIP.2004.1421349}, author = {Han,Bohyung and Davis, Larry S.} } @conference {12288, title = {Slurpie: a cooperative bulk data transfer protocol}, booktitle = {INFOCOM 2004. Twenty-third AnnualJoint Conference of the IEEE Computer and Communications Societies}, volume = {2}, year = {2004}, month = {2004/03//}, pages = {941 - 951 vol.2 - 941 - 951 vol.2}, abstract = {We present Slurpie: a peer-to-peer protocol for bulk data transfer. Slurpie is specifically designed to reduce client download times for large, popular files, and to reduce load on servers that serve these files. Slurpie employs a novel adaptive downloading strategy to increase client performance, and employs a randomized backoff strategy to precisely control load on the server. We describe a full implementation of the Slurpie protocol, and present results from both controlled local-area and wide-area testbeds. Our results show that Slurpie clients improve performance as the size of the network increases, and the server is completely insulated from large flash crowds entering the Slurpie network.}, keywords = {adaptive, bulk, client-server, clients;, computing;, cooperative, data, data;, downloading, network;, peer-to-peer, protocol;, protocols;, Slurpie, strategy;, systems;, transfer, transport}, doi = {10.1109/INFCOM.2004.1356981}, author = {Sherwood,R. and Braud,R. and Bhattacharjee, Bobby} } @article {12719, title = {Accurate dense optical flow estimation using adaptive structure tensors and a parametric model}, journal = {Image Processing, IEEE Transactions on}, volume = {12}, year = {2003}, month = {2003/10//}, pages = {1170 - 1180}, abstract = {An accurate optical flow estimation algorithm is proposed in this paper. By combining the three-dimensional (3D) structure tensor with a parametric flow model, the optical flow estimation problem is converted to a generalized eigenvalue problem. The optical flow can be accurately estimated from the generalized eigenvectors. The confidence measure derived from the generalized eigenvalues is used to adaptively adjust the coherent motion region to further improve the accuracy. Experiments using both synthetic sequences with ground truth and real sequences illustrate our method. Comparisons with classical and recently published methods are also given to demonstrate the accuracy of our algorithm.}, keywords = {3D, accuracy;, adaptive, and, coherent, confidence, dense, eigenfunctions;, eigenvalue, eigenvalues, eigenvectors;, estimation;, flow, generalized, ground, image, measure;, model;, MOTION, optical, parameter, parametric, problem;, real, region;, sequences;, structure, synthetic, tensor;, tensors;, three-dimensional, truth;}, isbn = {1057-7149}, doi = {10.1109/TIP.2003.815296}, author = {Liu,Haiying and Chellapa, Rama and Rosenfeld, A.} } @conference {12723, title = {Adaptive visual tracking and recognition using particle filters}, booktitle = {Multimedia and Expo, 2003. ICME {\textquoteright}03. Proceedings. 2003 International Conference on}, volume = {2}, year = {2003}, month = {2003/07//}, pages = {II - 349-52 vol.2 - II - 349-52 vol.2}, abstract = {This paper presents an improved method for simultaneous tracking and recognition of human faces from video, where a time series model is used to resolve the uncertainties in tracking and recognition. The improvements mainly arise from three aspects: (i) modeling the inter-frame appearance changes within the video sequence using an adaptive appearance model and an adaptive-velocity motion model; (ii) modeling the appearance changes between the video frames and gallery images by constructing intra- and extra-personal spaces; and (iii) utilization of the fact that the gallery images are in frontal views. By embedding them in a particle filter, we are able to achieve a stabilized tracker and an accurate recognizer when confronted by pose and illumination variations.}, keywords = {adaptive, adaptive-velocity, appearance, extra-personal, Filtering, filters;, image, intra-personal, model;, MOTION, particle, processing;, recognition;, sequence;, sequences;, series, signal, spaces;, theory;, TIME, tracking;, video, visual}, doi = {10.1109/ICME.2003.1221625}, author = {Zhou,Shaohua and Chellapa, Rama and Moghaddam, B.} } @article {18193, title = {Data hiding in image and video .I. Fundamental issues and solutions}, journal = {Image Processing, IEEE Transactions on}, volume = {12}, year = {2003}, month = {2003/06//}, pages = {685 - 695}, abstract = {We address a number of fundamental issues of data hiding in image and video and propose general solutions to them. We begin with a review of two major types of embedding, based on which we propose a new multilevel embedding framework to allow the amount of extractable data to be adaptive according to the actual noise condition. We then study the issues of hiding multiple bits through a comparison of various modulation and multiplexing techniques. Finally, the nonstationary nature of visual signals leads to highly uneven distribution of embedding capacity and causes difficulty in data hiding. We propose an adaptive solution switching between using constant embedding rate with shuffling and using variable embedding rate with embedded control bits. We verify the effectiveness of our proposed solutions through analysis and simulation.}, keywords = {adaptive, analysis;, bits;, colour, condition;, constant, CONTROL, data, embedded, EMBEDDING, embedding;, encapsulation;, extractable, hiding;, image, Modulation, modulation;, multilevel, multiplexing, multiplexing;, NOISE, nonstationary, processing;, rate;, reviews;, shuffling;, signal, signals;, simulation;, solution;, techniques;, variable, video, visual}, isbn = {1057-7149}, doi = {10.1109/TIP.2003.810588}, author = {M. Wu and Liu,Bede} } @conference {13237, title = {Improved fast gauss transform and efficient kernel density estimation}, booktitle = {Computer Vision, 2003. Proceedings. Ninth IEEE International Conference on}, year = {2003}, month = {2003/10//}, pages = {664 -671 vol.1 - 664 -671 vol.1}, abstract = {Evaluating sums of multivariate Gaussians is a common computational task in computer vision and pattern recognition, including in the general and powerful kernel density estimation technique. The quadratic computational complexity of the summation is a significant barrier to the scalability of this algorithm to practical applications. The fast Gauss transform (FGT) has successfully accelerated the kernel density estimation to linear running time for low-dimensional problems. Unfortunately, the cost of a direct extension of the FGT to higher-dimensional problems grows exponentially with dimension, making it impractical for dimensions above 3. We develop an improved fast Gauss transform to efficiently estimate sums of Gaussians in higher dimensions, where a new multivariate expansion scheme and an adaptive space subdivision technique dramatically improve the performance. The improved FGT has been applied to the mean shift algorithm achieving linear computational complexity. Experimental results demonstrate the efficiency and effectiveness of our algorithm.}, keywords = {adaptive, algorithm;multivariate, complexity;computer, complexity;Gaussian, computational, density, estimation;mean, expansion, Gauss, processes;computational, recognition;quadratic, scheme;pattern, shift, space, subdivision, technique;computer, theory;, transform;kernel, vision;estimation, vision;fast}, doi = {10.1109/ICCV.2003.1238383}, author = {Yang,C. and Duraiswami, Ramani and Gumerov, Nail A. and Davis, Larry S.} } @conference {18288, title = {Video access control via multi-level data hiding}, booktitle = {Multimedia and Expo, 2000. ICME 2000. 2000 IEEE International Conference on}, volume = {1}, year = {2000}, month = {2000///}, pages = {381 -384 vol.1 - 381 -384 vol.1}, abstract = {The paper proposes novel data hiding algorithms and system design for high quality digital video. Instead of targeting on a single degree of robustness, which results in overestimation and/or underestimation of the noise conditions, we apply multi-level embedding to digital video to achieve more than one level of robustness-capacity tradeoff. In addition, an adaptive technique is proposed to determine how many bits are embedded in each part of the video. Besides user data, control information such as synchronization and the number of hidden user bits are embedded as well. The algorithm can be used for applications such as access control}, keywords = {access, adaptive, algorithms;hidden, bits;high, conditions;robustness;robustness-capacity, control;adaptive, data, data;video, design;user, digital, embedding;noise, encapsulation;multimedia, hiding, hiding;multi-level, information;data, processing;, QUALITY, signal, systems;authorisation;data, systems;video, technique;control, tradeoff;system, user, video;multi-level}, doi = {10.1109/ICME.2000.869620}, author = {M. Wu and Yu,Hong Heather} } @article {17969, title = {Adaptive real-time level-of-detail based rendering for polygonal models}, journal = {Visualization and Computer Graphics, IEEE Transactions on}, volume = {3}, year = {1997}, month = {1997/06//apr}, pages = {171 - 183}, abstract = {We present an algorithm for performing adaptive real-time level-of-detail-based rendering for triangulated polygonal models. The simplifications are dependent on viewing direction, lighting, and visibility and are performed by taking advantage of image-space, object-space, and frame-to-frame coherences. In contrast to the traditional approaches of precomputing a fixed number of level-of-detail representations for a given object, our approach involves statically generating a continuous level-of-detail representation for the object. This representation is then used at run time to guide the selection of appropriate triangles for display. The list of displayed triangles is updated incrementally from one frame to the next. Our approach is more effective than the current level-of-detail-based rendering approaches for most scientific visualization applications, where there are a limited number of highly complex objects that stay relatively close to the viewer. Our approach is applicable for scalar (such as distance from the viewer) as well as vector (such as normal direction) attributes}, keywords = {(computer, adaptive, attributes;scientific, attributes;view-dependent, coherence;image-space;lighting;multiresolution, direction;visibility;computational, geometry;data, graphics);, hierarchies;object-space;run, hierarchies;triangulated, level-of-detail, models;vector, polygonal, real-time, refinement;triangle, rendering;displayed, simplifications;viewing, systems;rendering, time;scalar, triangles;frame-to-frame, visualisation;real-time, visualization;selective}, isbn = {1077-2626}, doi = {10.1109/2945.597799}, author = {Xia,J. C and El-Sana,J. and Varshney, Amitabh} }