Detection of small changes in airborne hyperspectral imagery: Experimental results over urban areas

2011 ◽  
Author(s):  
Salvatore Resta ◽  
Nicola Acito ◽  
Marco Diani ◽  
Giovanni Corsini ◽  
Thomas Opsahl ◽  
...  
Keyword(s):  
Urban Areas ◽  
Hyperspectral Imagery ◽  
Experimental Results

scholarly journals An evolutionary solution for multimodal shortest path problem in metropolises

2010 ◽  
Vol 7 (4) ◽  
pp. 789-811 ◽  
Author(s):  
Rahim Abbaspour ◽  
Farhad Samadzadegan
Keyword(s):  
Evolutionary Algorithm ◽  
Shortest Path ◽  
Urban Areas ◽  
Shortest Path Problem ◽  
Experimental Results ◽  
Time Dependent ◽  
Research Focus ◽  
Problem Of Time ◽  
Optimum Path

This paper addresses the problem of time-dependent shortest multimodal path in complex and large urban areas. This problem is one of the important and practical problems in several fields such as transportation, and recently attracts the research focus due to developments in new application areas. An adapted evolutionary algorithm, in which chromosomes with variable lengths and particularly defined evolutionary stages were used, was employed to solve the problem. The proposed solution was tested over the dataset of city of Tehran. The evaluation consists of computing shortest multimodal path between 250 randomly selected pairs of origins and destination points with different distances. It was assumed that three modes of walking, bus, and subway are used to travel between points. Moreover, some tests were conducted over the dataset to illustrate the robustness of method. The experimental results and related indices such as convergence plot show that the proposed algorithm can find optimum path according to applied constraints.

Processing of Hyperspectral Imagery for Contamination Detection in Urban Areas

2011 ◽  
pp. 147-156 ◽  
Author(s):  
Mikhail A. Popov ◽  
Sergey A. Stankevich ◽  
Ludmila P. Lischenko ◽  
Vladimir V. Lukin ◽  
Nikolay N. Ponomarenko
Keyword(s):  
Urban Areas ◽  
Hyperspectral Imagery

Anomaly Detection in Hyperspectral Imagery Based on Spectral Gradient and LLE

2011 ◽  
Vol 121-126 ◽  
pp. 720-724
Author(s):  
Liang Liang Wang ◽  
Zhi Yong Li ◽  
Ji Xiang Sun
Keyword(s):  
Anomaly Detection ◽  
Euclidean Distance ◽  
Hyperspectral Imagery ◽  
Detection Algorithm ◽  
Hyperspectral Data ◽  
Experimental Results ◽  
Feature Analysis ◽  
Detection Problem ◽  
Local Linear Embedding ◽  
Linear Embedding

The local linear embedding algorithm(LLE) is applied into the anomaly detection algorithm on the basis of the feature analysis of the hyperspectral data. Then, to deal with the problem of declining capacity of identifying the neighborhood caused by the Euclidean distance, an improved LLE algorithm is developed. The improved LLE algorithm selects neighborhood pixels according to the spectral gradient, thus making the anomaly detection more robust to the changes of light and terrain. Experimental results prove the feasibility of using LLE algorithm to solve the anomaly detection problem, and the effectiveness of the algorithm in improving the detection performance.

New Measure Based Manifold Algorithm and Application in Anomaly Detection of Hyperspectral Imagery

2011 ◽  
Vol 80-81 ◽  
pp. 797-803
Author(s):  
Liang Liang Wang ◽  
Zhi Yong Li ◽  
Ji Xiang Sun ◽  
Chun Du
Keyword(s):  
Anomaly Detection ◽  
Manifold Learning ◽  
High Dimension ◽  
Learning Algorithm ◽  
Hyperspectral Imagery ◽  
Detection Performance ◽  
Hyperspectral Data ◽  
Experimental Results ◽  
Nonlinear Structure ◽  
Spectral Angle

Hyperspectral data is endowed with characteristics of intrinsic nonlinear structure and high dimension. In this paper, a nonlinear manifold learning algorithm - ISOMAP is applied to anomaly detection. Then an improved ISOMAP algorithm is developed based on the analysis of the inherent characteristics of hyperspectral imagery. The improved ISOMAP algorithm selects neighborhood according to a novel measure of combination of spectral gradient and spectral angle in order to make the algorithm more robust to the changes of light and terrain. Experimental results prove the effectiveness of the algorithm in improving the detection performance.

scholarly journals Spatiotemporal Analysis of Taxi-Driver Shifts Using Big Trace Data

2020 ◽  
Vol 9 (4) ◽  
pp. 281
Author(s):  
Luling Cheng ◽  
Xue Yang ◽  
Luliang Tang ◽  
Qian Duan ◽  
Zihan Kan ◽  
...  
Keyword(s):  
Urban Areas ◽  
Spatiotemporal Analysis ◽  
Gaussian Mixture ◽  
Recall Rate ◽  
Experimental Results ◽  
Sequential Patterns ◽  
Taxi Driver ◽  
Demand And Supply ◽  
Trace Data ◽  
The City

In taxi management, taxi-driver shift behaviors play a key role in arranging the operation of taxis, which affect the balance between the demand and supply of taxis and the parking spaces. At the same time, these behaviors influence the daily travel of citizens. An analysis of the distribution of taxi-driver shifts, therefore, contributes to transportation management. Compared to the previous research using the real shift records, this study focuses on the spatiotemporal analysis of taxi-driver shifts using big trace data. A two-step strategy is proposed to automatically identify taxi-driver shifts from big trace data without the information of drivers’ identities. The first step is to pick out the frequent spatiotemporal sequential patterns from all parking events based on the spatiotemporal sequence analysis. The second step is to construct a Gaussian mixture model based on prior knowledge for further identifying taxi-driver shifts from all frequent spatiotemporal sequential patterns. The spatiotemporal distribution of taxi-driver shifts is analyzed based on two indicators, namely regional taxi coverage intensity and taxi density. Taking the city of Wuhan as an example, the experimental results show that the identification precision and recall rate of taxi-driver shift events based on the proposed method can achieve about 95% and 90%, respectively, by using big taxi trace data. The occurrence time of taxi-driver shifts in Wuhan mainly has two high peak periods: 1:00 a.m. to 4:00 a.m. and 4:00 p.m. to 5:00 p.m. Although taxi-driver shift behaviors are prohibited during the evening peak hour based on the regulation issued by Wuhan traffic administration, experimental results show that there are still some drivers in violation of this regulation. By analyzing the spatial distribution of taxi-driver shifts, we find that most taxi-driver shifts distribute in central urban areas such as Wuchang and Jianghan district.

scholarly journals Ku Band Terrestrial Radar Observations by Means of Circular Polarized Antennas

2019 ◽  
Vol 11 (3) ◽  
pp. 270 ◽  
Author(s):  
Guido Luzi ◽  
Niccolò Dematteis
Keyword(s):  
Circular Polarization ◽  
Urban Areas ◽  
Experimental Results ◽  
Radar Interferometry ◽  
Vertical Polarization ◽  
Radar Images ◽  
Polarization Response ◽  
First Time ◽  
Natural Media ◽  
Ku Band

This paper reports some experimental results obtained by means of a commercial apparatus used by many researchers and users, where a pair of novel and specifically developed circular polarized antennas, designed to operate with Ku band-terrestrial radar interferometers, are used alternatively to the most conventional linear vertical polarized horns provided by the manufacturer of the apparatus. These radar acquisitions have been carried out to investigate for the first time the potential of circular polarization (CP) configurations for terrestrial radar interferometers (TRI) applications, aiming at improving monitoring of landslides, mines, and semi-urban areas. The study tries to evaluate whether the circular polarization response of natural and man-made targets can improve the interpretation of the radar images, with respect to the standard approach used in terrestrial radar interferometry, usually carried out in co-polar vertical polarization. The goal is to investigate how different polarization combinations, in terrestrial radar interferometry, affect the coherence and amplitude dispersion of natural media, potentially improving the identification of stable scatter.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

A new dissociation mode for dislocations in silicon

1978 ◽  
Vol 36 (1) ◽  
pp. 346-347
Author(s):  
A. Ourmazd ◽  
G.R. Booker ◽  
C.J. Humphreys
Keyword(s):  
Detailed Examination ◽  
Experimental Results ◽  
Dislocation Network ◽  
Weak Beam ◽  
Phosphorus Doped

A (111) phosphorus-doped Si specimen, thinned to give a TEM foil of thickness ∼ 150nm, contained a dislocation network lying on the (111) plane. The dislocation lines were along the three <211> directions and their total Burgers vectors,ḇt, were of the type , each dislocation being of edge character. TEM examination under proper weak-beam conditions seemed initially to show the standard contrast behaviour for such dislocations, indicating some dislocation segments were undissociated (contrast A), while other segments were dissociated to give two Shockley partials separated by approximately 6nm (contrast B) . A more detailed examination, however, revealed that some segments exhibited a third and anomalous contrast behaviour (contrast C), interpreted here as being due to a new dissociation not previously reported. Experimental results obtained for a dislocation along [211] with for the six <220> type reflections using (g,5g) weak-beam conditions are summarised in the table below, together with the relevant values.

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