Encoding geometric information in road networks extracted from binary images

2005 ◽  
Vol 32 (2) ◽  
pp. 179-190
Author(s):  
Rui Carvalho ◽  
Michael Batty
Keyword(s):  
Road Networks ◽  
Geometric Information ◽  
Binary Images

Encoding Geometric Information in Road Networks Extracted from Binary Images

2005 ◽  
Vol 32 (2) ◽  
pp. 179-190 ◽  
Author(s):  
Rui Carvalho ◽  
Michael Batty
Keyword(s):  
Road Networks ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Automatic Extraction ◽  
Digital Imagery ◽  
Geometric Information ◽  
Line Segments ◽  
Binary Images ◽  
Recent Developments ◽  
The Individual

The authors discuss recent progress in extracting road networks from digital imagery. We briefly review recent developments in methods for the automatic extraction of road centre line networks and propose a related algorithm aimed at encoding the geometry of road networks with line segments. Our algorithm is inspired by ‘axial lines’, which have been defined as lines of uninterrupted movement within urban streetscapes or buildings. We show that axial lines appear as ridges in isovist fields. These are formed from the maximum diametric lengths of the individual isovists, sometimes called viewsheds, which make up these fields. We present an image-processing technique for the identification of lines from ridges, discuss current strengths and weaknesses of the method, and show how it can be implemented easily and effectively.

Test on Meso-Damage Data of Marble under Dynamic Load

2011 ◽  
Vol 105-107 ◽  
pp. 1484-1487
Author(s):  
Xiao Hui Ni ◽  
Xiao Juan Li
Keyword(s):  
Digital Technology ◽  
Surrounding Rock ◽  
Practical Significance ◽  
Marble Sample ◽  
Geometric Information ◽  
Binary Images ◽  
Testing Scheme ◽  
Damage Data ◽  
Length Width ◽  
Meso Scale

The failure damage of granite under axial load are caused by the propagation and coalescent of cracks at mesoscale, so it is of important theoretical value and practical significance to to understand the mechnical properties of rock by experimental research on meso damage of granite. The microfracturing process of the pre-crack marble sample on surrounding rock in immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression is recorded by using the testing scheme. According to stereology theory, the propagation and coalescent of cracks at meso-scale are quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, is obtained from binary images after segmentation. The results show that the new meso-mechanical testing scheme on rock meso-damage could be used to quantitatively analyzed from the geometric information of rock microcracks.

Meso-Mechanical Testing Scheme on Rock Meso-Damage Based on Digital Image Processing Technique

2011 ◽  
Vol 261-263 ◽  
pp. 1635-1639
Author(s):  
Xiao Hui Ni
Keyword(s):  
Mechanical Testing ◽  
Digital Technology ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Practical Significance ◽  
Marble Sample ◽  
Geometric Information ◽  
Binary Images ◽  
Testing Scheme ◽  
Length Width

The failure damage of granite under axial load are caused by the propagation and coalescent of cracks at mesoscale, so it is of important theoretical value and practical significance to to understand the mechnical properties of rock by experimental research on meso damage of granite. The microfracturing process of the pre-crack marble sample on surrounding rock in immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression is recorded by using the testing scheme. According to stereology theory, the propagation and coalescent of cracks at meso-scale are quantitatively investigated with digital technology. Therefore, the basic geometric information of rock microcracks such as area, angle, length, width, perimeter, is obtained from binary images after segmentation. The results show that the new meso-mechanical testing scheme on rock meso-damage could be used to quantitatively analyzed from the geometric information of rock microcracks.

On the Shape of Field-Ion Emitters

1976 ◽  
Vol 34 ◽  
pp. 520-521
Author(s):  
H.C. Eaton ◽  
B.N. Ranganathan ◽  
T.W. Burwinkle ◽  
R. J. Bayuzick ◽  
J.J. Hren
Keyword(s):  
Grain Boundary ◽  
Spherical Shape ◽  
Theoretical Strength ◽  
Evaporation Process ◽  
Field Evaporation ◽  
Geometric Information ◽  
Field Ion Microscopy ◽  
Considerable Error ◽  
True Shape ◽  
Ion Microscopy

The shape of the emitter is of cardinal importance to field-ion microscopy. First, the field evaporation process itself is closely related to the initial tip shape. Secondly, the imaging stress, which is near the theoretical strength of the material and intrinsic to the imaging process, cannot be characterized without knowledge of the emitter shape. Finally, the problem of obtaining quantitative geometric information from the micrograph cannot be solved without knowing the shape. Previously published grain-boundary topographies were obtained employing an assumption of a spherical shape (1). The present investigation shows that the true shape deviates as much as 100 Å from sphericity and boundary reconstructions contain considerable error as a result.Our present procedures for obtaining tip shape may be summarized as follows. An empirical projection, D=f(θ), is obtained by digitizing the positions of poles on a field-ion micrograph.

Continuous K Nearest Neighbor Queries of Moving Objects in Road Networks

2010 ◽  
Vol 33 (8) ◽  
pp. 1396-1404 ◽  
Author(s):  
Liang ZHAO ◽  
Luo CHEN ◽  
Ning JING ◽  
Wei LIAO
Keyword(s):  
Moving Objects ◽  
Nearest Neighbor ◽  
Road Networks ◽  
Nearest Neighbor Queries

NNlists-based k-path nearest neighbor query in road networks

2010 ◽  
Vol 30 (7) ◽  
pp. 1947-1949
Author(s):  
Bao-wen WANG ◽  
Jing-jing HAN ◽  
Zi-jun CHEN ◽  
Wen-yuan LIU
Keyword(s):  
Nearest Neighbor ◽  
Road Networks ◽  
Nearest Neighbor Query
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