Three-dimensional depth information of a surface can be encoded in a two-dimensional image called single-image random-dot-stereograms or, more widely known, autostereograms. It is achieved by using the correlations of...
详细信息
ISBN:
(纸本)0780370414
Three-dimensional depth information of a surface can be encoded in a two-dimensional image called single-image random-dot-stereograms or, more widely known, autostereograms. It is achieved by using the correlations of pixels in the horizontal direction. Using the correspondences between pixels in human brains or computer algorithms, surfaces can be reconstructed from autostereograms. However, in some cases, the reconstructed surfaces are not unique because of "echoes". In the presence of echoes, reconstruction of the original surface from an autostereogram cannot be guaranteed since no cue of the original surface is available in autostereograms. In this paper, the causes of echoes are investigated and conditions for echo-free reconstructions are derived. Based on these conditions, an improved autostereogram generation algorithm is proposed to guarantee echo-free autostereograms. Besides, the surface reconstruction algorithm is modified such that the originally encoded surfaces can always be reconstructed from echo-free autostereograms.
In this paper two new adaptive equalizers are proposed which belong to the quasi-Newton (QN) algorithmic family. The first algorithm is a Linear Equalizer (LE) and the second one is a Decision Feedback Equalizer (DFE)...
详细信息
ISBN:
(纸本)0780370414
In this paper two new adaptive equalizers are proposed which belong to the quasi-Newton (QN) algorithmic family. The first algorithm is a Linear Equalizer (LE) and the second one is a Decision Feedback Equalizer (DFE). In the LE case the involved inverse Hessian matrix is approximated by a proper expansion consisting of powers of a Toeplitz matrix. Due to this formulation the algorithm can be efficiently implemented in the transform domain (TD) using FFT. The same idea is applied to the Feedforward part of the DFE. The derived algorithms enjoy the advantages of QN algorithms, that is, they exhibit faster convergence than their stochastic gradient counterparts and less computational complexity as compared to other Newton-type algorithms. These advantages are further enhanced due to TD implementation.
Evolving networks of ad-hoc, wireless sensing nodes rely heavily on the ability to establish position information. The algorithms presented herein rely on range measurements between pairs of nodes and the a priori coo...
详细信息
ISBN:
(纸本)0780370414
Evolving networks of ad-hoc, wireless sensing nodes rely heavily on the ability to establish position information. The algorithms presented herein rely on range measurements between pairs of nodes and the a priori coordinates of sparsely located anchor nodes. Clusters of nodes surrounding anchor nodes cooperatively establish confident position estimates through assumptions, checks, and iterative refinements. Once established, these positions are propagated to more distant nodes, allowing the entire network to create an accurate map of itself. Major obstacles include overcoming inaccuracies in range measurements as great as +/-50%, as well as the development of initial guesses for node locations in clusters with few or no anchor nodes. Solutions to these problems are presented and discussed, using position error as the primary metric. algorithms are compared according to position error, scalability, and communication and computational requirements. Early simulations yield average position errors of 5% in the presence of both range and initial position inaccuracies.
The main contribution of this work is to show that a number of fundamental and seemingly unrelated problems in database design, pattern recognition, robotics, computational geometry, and imageprocessing can be solved...
详细信息
The main contribution of this work is to show that a number of fundamental and seemingly unrelated problems in database design, pattern recognition, robotics, computational geometry, and imageprocessing can be solved simply and elegantly by stating them as instances of a unifying algorithmic framework that we call the Multiple Query problem. The Multiple Query problem (MQ, for short) is a 5-tuple (Q,A,D,phi,circle plus), where Q is a set of queries, A is a set of items, D is a set of solutions, phi : Q x A --> D is a function, and circle plus is a commutative and associative binary operator over D. The input to the MQ problem consists of a sequence Q = (q(1),q(2),...,q(m) ) of m queries from Q and of a sequence A = (a(1),a(2,)...a(n)) of n items from A. The goal is to compute, for every query q(i) (I less than or equal to i less than or equal to m) its solution defined as phi (q(b),A) = phi (q(i),a(2)) circle plus ... circle plus phi (q(i),a(n)). We begin by discussing a generic algorithm that solves a large class of MQ problems in O(rootm + f(n)) time on a reconfigurable mesh of size rootn x rootn, where f (n) is the time necessary to compute the expression d(1) circle plus d(2) circle plus (...) circle plus d(n) with d(n) is an element of D on such a platform. We then go on to show that the MQ framework affords us an optimal algorithm for the multiple point location problem on a reconfigurable mesh of size rootn x rootn. Given a set A of n points and a set Q of m (m less than or equal to n) points in the plane, our algorithm reports, in O(rootm + log log n) time, all points of Q that lie inside the convex hull of A. Quite surprisingly, our algorithm solves the multiple point location problem without computing the convex hull of A which, in itself, takes Omega(rootn) time on a reconfigurable mesh of size rootn x rootn. Finally, we prove an Omega(rootm + g(n)) time lower bound for nontrivial MQ problems, where g(n) is the lower bound for evaluating the expression d
Deblocking and deringing are two video post-processing techniques largely used to remove coding artifacts and improve the visual quality when rendering low bit rate coded video. The algorithms used to achieve these ta...
详细信息
ISBN:
(纸本)0780370414
Deblocking and deringing are two video post-processing techniques largely used to remove coding artifacts and improve the visual quality when rendering low bit rate coded video. The algorithms used to achieve these tasks are computationally intensive and usually require high speed processors to be able to run in real time. Efficient implementations of signal adaptive filters for video post-processing can be obtained using the specialized features of the parallel BOPS(R) DSP cores. The performance achieved by deblocking and deringing CIF and SDTv size video sequences on the MANTA(TM) prototype chip are illustrated. It is shown that such complex tasks may be executed at low clock rates using the BOPS ManArray(TM) technology.
The influence of the measurement errors can be reduced using multi sensors fusion techniques. The competitive algorithms are one of the perspective class of sensor fusion (SF) algorithms, which are used in sensor fusi...
详细信息
ISBN:
(纸本)078037164X
The influence of the measurement errors can be reduced using multi sensors fusion techniques. The competitive algorithms are one of the perspective class of sensor fusion (SF) algorithms, which are used in sensor fusion techniques daring processing of sensor's measurements for receive more accurate measurement result than measurement results of each single sensor.
作者：
Keshava, NMIT
Lincoln Lab Lexington MA 02420 USA
In this paper, we explore the role of best bands algorithms in the context of maximizing the performance of hyperspectral algorithms. Specifically, we first focus on creating art intuitive framework for how metrics qu...
详细信息
ISBN:
(纸本)0780370414
In this paper, we explore the role of best bands algorithms in the context of maximizing the performance of hyperspectral algorithms. Specifically, we first focus on creating art intuitive framework for how metrics quantify the distance between two spectra. Focusing on the Spectral Angle Mapper (SAM) metric, we demonstrate how the separability of two spectra can be increased by choosing the bands that maximize the metric. This intuition about best bands analysis for SAM is extended to the Generalized Likelihood Ratio Test (GLRT) for a practical target/background detection scenario. Results are shown for a scene imaged by the HYDICE sensor demonstrating that the separability of targets and background can be increased by carefully choosing the bands for the test.
This paper analyzes the asymptotic performance of Maximum Likelihood (ML) channel estimation algorithms in wideband code division multiple access (WCDMA) scenarios. We concentrate on systems with periodic spreading se...
详细信息
ISBN:
(纸本)0780370414
This paper analyzes the asymptotic performance of Maximum Likelihood (ML) channel estimation algorithms in wideband code division multiple access (WCDMA) scenarios. We concentrate on systems with periodic spreading sequences (period larger than or equal to the symbol span) with high spreading factors, where the transmitted signal contains a code division multiplexed pilot for channel estimation purposes. Assuming randomized training and code sequences, we derive and compare the asymptotic covariances of the training-only (TO), semi-blind conditional ML (CML) and semi-blind Gaussian ML (GML) channel estimators.
In this paper, we bring local phase and multiresolution analysis to the texture segmentation problem. A Markov random field characterization is still employed, except it is used to model phase correlations rather than...
详细信息
ISBN:
(纸本)0780370414
In this paper, we bring local phase and multiresolution analysis to the texture segmentation problem. A Markov random field characterization is still employed, except it is used to model phase correlations rather than intensity correlations. Since statistical characteristics of phase are typically quite different to those of intensity, there exists the potential for creating greater discrimination in its feature space. We apply the Wreath Product Transform and use the phase at higher scales to initiate the segmentation process. For textures defined by homogeneous regions of dominant local edges, we see that the new algorithm yields better segmentation than that obtained through conventional multiresolution algorithms based on lowpass data.
We present a new multimodal system that combines stereoscopic and audio-based source localization to track the position of a flying bat. Also presented are novel algorithms for audio source localization. The bat was a...
详细信息
ISBN:
(纸本)0780370414
We present a new multimodal system that combines stereoscopic and audio-based source localization to track the position of a flying bat. Also presented are novel algorithms for audio source localization. The bat was allowed to fly in an anechoic room and monitored by two high-speed video cameras. The vocalizations of the bat were simultaneously recorded from six microphones. The data was then processed offline to localize the source and reconstruct the trajectory of the bat. We compare the performance of the localization algorithm with the position data obtained from stereoscopic pictures of the bat. The results confirm that the stereoscopic analysis and the audio localization are in good agreement. This system opens up new possibilities for performing multimodal research and developing more tightly integrated algorithms.
暂无评论