Modern image processing techniques increasingly use prior models of the expected distribution of objects. Principal component eigen-models are often selected for shape prior modeling, but are limited in capturing only...
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Modern image processing techniques increasingly use prior models of the expected distribution of objects. Principal component eigen-models are often selected for shape prior modeling, but are limited in capturing only the second order moment statistics. On the other hand, kernel densities can in concept reproduce arbitrary statistics, but are problematic for high dimensional data such as shapes. An evident approach is to combine these methods, using PCA to reduce the problem dimensionality, followed by kernel density modeling of the PCA coefficients. In this paper we show that useful algorithmic and editing operations can be formulated in term of this simple approach. The operations are illustrated in the context of point distribution shape models. Particular points can be rapidly evaluated as being plausible or outliers, and a plausible shape can be completed given limited operator input in a manually guided procedure. This "PCA+KD" approach is conceptually simple, scalable (becoming increasingly accurate with additional training data), provides improved modeling power, and supports useful algorithmic queries.
Technology advances have made possible the visualization of electron temperature profiles and fluctuations inside the core of high temperature plasmas via a twodimensional passive millimeter wave imaging system. The e...
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ISBN:
(纸本)1424407494
Technology advances have made possible the visualization of electron temperature profiles and fluctuations inside the core of high temperature plasmas via a twodimensional passive millimeter wave imaging system. The electron cyclotron emission imaging (ECEI) system concept and configuration are briefly described. Advanced technologies such as frequency selective surfaces band-stop filter, planar Schottky diode mixer arrays, wide bandwidth IF electronics, and imaging optics are presented.
The development of imaging arrays on dielectric lens antennas for use in millimeter wave imaging systems is described. The 24-element 140-170 GHz and 22-element 110-140 GHz imaging mixer array are comprised of Schottk...
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The development of imaging arrays on dielectric lens antennas for use in millimeter wave imaging systems is described. The 24-element 140-170 GHz and 22-element 110-140 GHz imaging mixer array are comprised of Schottky diodes and double dipole antenna arrays placed on an elliptical lens. This paper first describes the antenna development and then the characterization of the off-axis performance of the elliptical lens. The unequal spacing between antennas and channel number of the antenna arrays are determined based on the theoretically calculated off-axis far field patterns. A wide bandwidth balun used to reduce the mixer IF loss is also described.
The design and experimental investigation of a D-Band coplanar stripline-fed double dipole antenna is presented. Double dipole antennas are designed for operation at 110-170 GHz as the imaging array elements for two m...
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ISBN:
(纸本)9781424408771;1424408776
The design and experimental investigation of a D-Band coplanar stripline-fed double dipole antenna is presented. Double dipole antennas are designed for operation at 110-170 GHz as the imaging array elements for two millimeter wave imaging systems for plasma diagnostics. The antenna patterns are measured on high density polyethylene (HDPE) elliptical lenses. The wide bandwidth antenna has clean patterns with low side lobe levels and narrow beam width, and thus can provide good image resolution and low inter-channel crosstalk.
Data stream clustering has emerged as a challenging and interesting problem over the past few years. Due to the evolving nature, and one-pass restriction imposed by the data stream model, traditional clustering algori...
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ISBN:
(纸本)1595934332
Data stream clustering has emerged as a challenging and interesting problem over the past few years. Due to the evolving nature, and one-pass restriction imposed by the data stream model, traditional clustering algorithms are inapplicable for stream clustering. This problem becomes even more challenging when the data is high-dimensional and the clusters are not linearly separable in the input space. In this paper, we propose a nonlinear stream clustering algorithm that adapts to the stream's evolutionary changes. Using the kernel methods for dealing with the non-linearity of data separation, we propose a novel 2-tier stream clustering architecture. Tier-1 captures the temporal locality in the stream, by partitioning it into segments, using a kernel-based novelty detection approach. Tier-2 exploits this segment structure to continuously project the streaming data nonlinearly onto a low-dimensional space (LDS), before assigning them to a cluster. We demonstrate the effectiveness of our approach through extensive experimental evaluation on various real-world datasets. Copyright 2006 ACM.
We present empirical measurements of the packet delivery performance of the Telos and MicaZ sensor platforms. At a high level, their behavior is similar to that of earlier platforms. They exhibit a reception "gre...
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ISBN:
(纸本)1595933433
We present empirical measurements of the packet delivery performance of the Telos and MicaZ sensor platforms. At a high level, their behavior is similar to that of earlier platforms. They exhibit a reception "grey region," and temporal variations in packet loss. Looking more deeply, however, there are subtle differences, and looking deeper still, the patterns behind these complexities become clear. Environmental noise (802.11b) has high spatial correlation. Packet loss occurs when a receiver operating near its noise floor experiences a small decrease in received signal strength, rather than an increase in environmental noise. These variations cause the reception "grey region." Packet losses are highly correlated over short time periods, but are independent over longer periods. Based on these findings, current practices could be easily changed that would greatly improve efficiency and performance.
Identifying or matching the surface color of a moving object in surveillance video is critical for achieving reliable object-tracking and searching. Traditional color models provide little help, since the surface of a...
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This paper describes work towards a mobile-robot following controller which has the ability to incorporate a leader's behavioral cues into its controller formulation. The paper presents the mathematical formulatio...
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ISBN:
(纸本)1424407265
This paper describes work towards a mobile-robot following controller which has the ability to incorporate a leader's behavioral cues into its controller formulation. The paper presents the mathematical formulation of the controller, and presents robot experimental studies used to investigate the controller. The controller continuously estimates the future predicted position of the leader (robot or human) as he/she/it moves, and then directs the follower robot to this position. A Kalman filter is employed for estimation that uses vision-based measurements of leader position, a dynamics model of the leader, and a behavioral-cue model of the leader. Singer's model is used to propagate the leader's state. A behavioral-cue model serves to create pseudo-measurements to further help the Kalman filter estimate the leader's future position. The controller is implemented on an ER Scorpion robot. Experiments are conducted using several different controllers. Results demonstrate that compared to other controllers, the proposed controller can more consistently follow the leader around sharp corners where line-of-sight is lost, as can happen often in indoor environments. However, in cases of more gradual movement where line-of-sight is not lost, a simpler vision-only controller has advantages.
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