Rock fissure pattern characterization by combining 1-D fractal dimension and statistical analysis

Wang, Weixing; Zheng, Shaokai; Lian, Renbao; Liang, Yajun

doi:10.1109/jas.2017.7510391

Cited by 5 publications

(5 citation statements)

References 17 publications

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“…In particular, in order to dissipate their angular momentum, particles on the disk are assumed to rotate around the central BH with a Keplerian velocity. Photons are assumed to be emitted from the disk according to an isotropic blackbody (BB) distribution at different temperatures, following a Novikov-Thorne radial profile (a multicolor disk, see Novikov & Thorne 1973;Wang 2000, see also Cunningham 1975 for a more complete relativistic treatment),…”

Section: The Modelmentioning

confidence: 99%

Towards a complete description of spectra and polarization of black hole accretion discs: albedo profiles and returning radiation

Taverna

Zhang

Dovčiak

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Accretion disks around stellar-mass black holes (BHs) emit radiation peaking in the soft Xrays when the source is in the thermal state. The emerging photons are polarized and, for symmetry reasons, the polarization integrated over the source is expected to be either parallel or perpendicular to the (projected) disk symmetry axis, because of electron scattering in the disk. However, due to General Relativity effects photon polarization vectors will rotate with respect to their original orientation, by an amount depending on both the BH spin and the observer's inclination. Hence, X-ray polarization measurements may provide important information about strong gravity effects around these sources. Along with the spectral and polarization properties of radiation which reaches directly the observer once emitted from the disk, in this paper we also include the contribution of returning radiation, i.e. photons that are bent by the strong BH gravity to return again on the disk, where they scatter until eventually escaping to infinity. A comparison between our results and those obtained in previous works by different authors show an overall good agreement, despite the use of different code architectures. We finally consider the effects of absorption in the disk material by including more realistic albedo profiles for the disk surface. Our findings in this respect show that considering also the ionization state of the disk may deeply modify the behavior of polarization observables.

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Section: The Modelmentioning

confidence: 99%

Towards a complete description of spectra and polarization of black hole accretion discs: albedo profiles and returning radiation

Taverna

Zhang

Dovčiak

et al. 2020

Monthly Notices of the Royal Astronomical Society

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show abstract

“…8(a), a road network is at the bottom of a mountain slope, the hillsides are covered with grass and light yellow color rock which has the similar color as road network has, therefore, the road network is difficult to detect. The Otsu [25], Dynamic thresholding [25], Canny [24],…”

Section: Results and Analysesmentioning

confidence: 99%

“…We use the maximum disk model based algorithm for object skeleton [1][2]24]. The algorithm simulates the process of the burning grass, that is to say, the medial axis locus can be obtained by utilizing the object's gradual evolution from edge to center.…”

Section: Road Central Line Detection In a Binary Imagementioning

confidence: 99%

Road extraction based on dynamic scale MSR and improved Canny in vague aerial images

wang

Feng

2022

Preprint

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Road extraction in vague aerial or remote sensing images is hard but significant. In this paper, a road extraction method for vague aerial images is studied. The method consists of four main algorithms: (1) a modified MSR algorithm to enhance a vague aerial road image, in which, the logarithm transform is applied first, then the scales for Retinex are determined in light on the image depth by using the method of dark channel prior; (2) the enhanced image is roughly segmented based on the improved Canny edge detector with edge region expansion, then, edge image is thresholded by Otsu; (3) a number of post processing functions in a binary image is applied for gap linking and noise removal; and (4) the extracted roads are regulated by using the road shape features. In experiments, a number of vague aerial images of multiple roads were selected, and the algorithm comparison results show that the studied method is satisfactory for the road extraction in a vague aerial image, and it is much better than other traditional algorithms.

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“…The main idea of the algorithm is to peel the boundary evenly again and again, and the result is that the boundary is the innermost part (otherwise it will affect the connectivity) to become the skeleton. Axis transformation algorithm [29] simulates the process of the burning grass, that is to say, the medial axis locus can be obtained by applying the object's gradual evolution from edge to center. The main idea is to uniformly peel the edges layer by layer, and consequently, the rest of the inner-most layer can be in skeleton.…”

Section: Lane Line Skeleton Extractionmentioning

confidence: 99%

Lane Line Extraction in Raining Weather Images by Ridge Edge Detection with Improved MSR and Hessian Matrix

Wang¹,

Berholm²,

Hu³

et al. 2021

ITC

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To accurately detect lane lines in road traffic images at raining weather, a edge detection based method is studied, which mainly includes four algorithms. (1) Firstly an image is enhanced by an improved Retinex algorithm; (2) Then, an algorithm based on the Hessian matrix is applied to strengthen lane lines; (3) To extract the feature points of a lane line, a ridge edge detection algorithm based on five line detection in four directions is proposed, in which, in light on the possible positions of lane lines in the image, it detects the maximum gray level points in the local area of the detecting point within the pre-set valid detection region; and (4) After the noise removal based on the minimum circumscribed rectangles, the candidate points of lane lines are connected as segments, and for the gap filling between segments, in order to make connection correctly, the algorithm makes the filling in two steps, short gap and long gap fillings, and the long gap filling is made on the combination of segment angle difference and gap distance and gap angle. By testing hundreds of images of the lane lines at raining weather and by comparing several traditional image enhancement and segmentation algorithms, the new method of the lane line detection can produce the satisfactory results.

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Rock fissure pattern characterization by combining 1-D fractal dimension and statistical analysis

Cited by 5 publications

References 17 publications

Towards a complete description of spectra and polarization of black hole accretion discs: albedo profiles and returning radiation

Towards a complete description of spectra and polarization of black hole accretion discs: albedo profiles and returning radiation

Road extraction based on dynamic scale MSR and improved Canny in vague aerial images

Lane Line Extraction in Raining Weather Images by Ridge Edge Detection with Improved MSR and Hessian Matrix

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