scholarly journals Use of high-frequency, high-definition topographic 3D data to develop geographic thinking of students

2019 ◽  
Author(s):  
Takuro Ogura ◽  
Yuichi S. Hayakawa ◽  
Hiroyuki Yamauchi ◽  
Takashi Oguchi ◽  
Yasuhiko Tamura ◽  
...  
Keyword(s):  
High Frequency ◽  
High Definition ◽  
3D Data ◽  
Geographic Thinking

High-Frequency and Passive Radar Designs for Homeland Security Applications

2011 ◽  
Vol 45 (3) ◽  
pp. 111-119 ◽  
Author(s):  
Magdy F. Iskander ◽  
Zhengqing Yun ◽  
Nuri Celik ◽  
Hyoungsun Youn ◽  
Nobutaka Omaki ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Homeland Security ◽  
High Frequency ◽  
Beam Steering ◽  
Antenna System ◽  
Hf Radar ◽  
Passive Radar ◽  
High Definition ◽  
Security Applications ◽  
The Impact

AbstractEmerging homeland security applications require low-cost and fast, deployable, high-frequency (HF) radar systems and the ability to operate in challenging terrain environments. With the need to cover as many border and coastal areas as possible, taking advantages of available transmitter resources to track targets using passive radar technologies is yet another area of research of considerable interest. In this paper, we describe the development of an HF radar system that meets these operational challenges, and we also highlight some recent implementation of the passive radar technology for homeland security applications. Specifically, we describe the design of a novel, electrically small HF antenna system consisting of three helical elements, one connected to the feed port while the other two are folded arms terminated with switchable loads. The antenna is 0.90-m (<3 feet) high with a small ground disk of 0.60 m (∼2 feet) diameter. The antenna is self-resonant at multiple frequencies (5.7, 16, 20.5, and 27.7 MHz) and with input impedance values that can be easily matched to a 50-Ω coaxial feed. Values of the electrical size ka range from 0.44 at 30 MHz down to 0.08 at 5.7 MHz. The achieved bandwidths range from 1.4% up to 12% and associated efficiencies range from 66.2% to 76% within the HF band (3‐30 MHz). As for the operational requirement in challenging terrain environments, a setup in a hilltop-type environment with a slope terrain and surface roughness was considered. A propagation modeling and ray-tracing approach was used to evaluate the impact of such terrain conditions on the effective interelement spacing of an HF radar antenna array and the subsequent impact on its beamforming and beam steering performance. It is shown that while the effect of the slope on the effective interelement spacing of the array could be very significant, diffraction effects from surface roughness resulted in a much smaller, but significant, error of about 18°. Results from some initial work on the implementation of passive radar technology, with focus on addressing the bandwidth requirement to ensure practical resolution values, are also described. It is shown that signals from wide-band transmitters (e.g., High Definition Television [HDTV] signals) rather than those from radio stations are required to provide acceptable range resolution. These as well as simulation and experimental results of the antenna design, and results from beamforming simulations illustrating the effect of a rough hilltop terrain on the HF radar performance are described.

3D Shape Compression Using Holoimage

2013 ◽  
pp. 939-956
Author(s):  
Nikolaus Karpinsky ◽  
Song Zhang
Keyword(s):  
Special Kind ◽  
Video Encoding ◽  
High Definition ◽  
Depth Data ◽  
Digital Fringe Projection ◽  
3D Data ◽  
3D Data Processing ◽  
Display Technology ◽  
Processing Techniques ◽  
2D Images

As 3D becomes more ubiquitous with the advent of 3D scanning and display technology, methods of compressing and transmitting 3D data need to be explored. One method of doing such is depth mapping, in which 3D depth data is compressed into a 2D image, and then 2D image processing techniques may be leveraged. This chapter presents a technique of depth mapping 3D scenes into 2D images, entitled Holoimage. In this technique, digital fringe projection, a special kind of structured light technique from optical metrology, is used to encode and decode 3D scenes pixel-by-pixel. Due to the pixel-by-pixel 3D data processing nature, this technique can be used on parallel hardware to realize real-time speed for high definition 3D video encoding and decoding.

3D Shape Compression Using Holoimage

2011 ◽  
pp. 87-104
Author(s):  
Nikolaus Karpinsky ◽  
Song Zhang
Keyword(s):  
Special Kind ◽  
Video Encoding ◽  
High Definition ◽  
Depth Data ◽  
Digital Fringe Projection ◽  
3D Data ◽  
3D Data Processing ◽  
Display Technology ◽  
Processing Techniques ◽  
2D Images

As 3D becomes more ubiquitous with the advent of 3D scanning and display technology, methods of compressing and transmitting 3D data need to be explored. One method of doing such is depth mapping, in which 3D depth data is compressed into a 2D image, and then 2D image processing techniques may be leveraged. This chapter presents a technique of depth mapping 3D scenes into 2D images, entitled Holoimage. In this technique, digital fringe projection, a special kind of structured light technique from optical metrology, is used to encode and decode 3D scenes pixel-by-pixel. Due to the pixel-by-pixel 3D data processing nature, this technique can be used on parallel hardware to realize real-time speed for high definition 3D video encoding and decoding.

scholarly journals A WEBGIS TO SUPPORT GPR 3D DATA ACQUISITION: A FIRST STEP FOR THE INTEGRATION OF UNDERGROUND UTILITY NETWORKS IN 3D CITY MODELS

2017 ◽  
Vol XLII-4/W7 ◽  
pp. 43-48 ◽  
Author(s):  
P. G. Tabarro ◽  
J. Pouliot ◽  
R. Fortier ◽  
L.-M. Losier
Keyword(s):  
Data Acquisition ◽  
Spatial Data ◽  
Relevant Information ◽  
Web Gis ◽  
Multiple Sources ◽  
High Definition ◽  
Large Cities ◽  
3D Data ◽  
Ground Penetrating ◽  
The Web

For the planning and sustainable development of large cities, it is critical to accurately locate and map, in 3D, existing underground utility networks (UUN) such as pipelines, cables, ducts, and channels. An emerging non-invasive instrument for collecting underground data such as UUN is the ground-penetrating radar (GPR). Although its capabilities, handling GPR and extracting relevant information from its data are not trivial tasks. For instance, both GPR and its complimentary software stack provide very few capabilities to co-visualize GPR collected data and other sources of spatial data such as orthophotography, DEM or road maps. Furthermore, the GPR interface lacks functionalities for adding annotation, editing geometric objects or querying attributes. A new approach to support GPR survey is proposed in this paper. This approach is based on the integration of multiple sources of geospatial datasets and the use of a Web-GIS system and relevant functionalities adapted to interoperable GPR data acquisition. The Web-GIS is developed as an improved module in an existing platform called GVX. The GVX-GPR module provides an interactive visualization of multiple layers of structured spatial data, including GPR profiles. This module offers new features when compared to traditional GPR surveys such as geo-annotated points of interest for identifying spatial clues in the GPR profiles, integration of city contextual data, high definition drone and satellite pictures, as-built, and more. The paper explains the engineering approach used to design and develop the Web GIS and tests for this survey approach, mapping and recording UUN as part of 3D city model.

scholarly journals DEVELOPING A LOW-COST SYSTEM FOR 3D DATA ACQUISITION

2017 ◽  
Vol XLII-2/W8 ◽  
pp. 119-126
Author(s):  
S. Kossieris ◽  
O. Kourounioti ◽  
P. Agrafiotis ◽  
A. Georgopoulos
Keyword(s):  
Data Acquisition ◽  
Low Cost ◽  
Outdoor Environment ◽  
High Definition ◽  
Processing Times ◽  
Cost System ◽  
3D Data ◽  
Viable Solution ◽  
3D Documentation ◽  
Greek Island

In this paper, a developed low-cost system is described, which aims to facilitate 3D documentation fast and reliably by acquiring the necessary data in outdoor environment for the 3D documentation of façades especially in the case of very narrow streets. In particular, it provides a viable solution for buildings up to 8-10m high and streets as narrow as 2m or even less. In cases like that, it is practically impossible or highly time-consuming to acquire images in a conventional way. This practice would lead to a huge number of images and long processing times. The developed system was tested in the narrow streets of a medieval village on the Greek island of Chios. There, in order to by-pass the problem of short taking distances, it was thought to use high definition action cameras together with a 360˚ camera, which are usually provided with very wide-angle lenses and are capable of acquiring images, of high definition, are rather cheap and, most importantly, extremely light. Results suggest that the system can perform fast 3D data acquisition adequate for deliverables of high quality.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

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