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Yin L.,Southwest Jiaotong University | Zhu J.,Southwest Jiaotong University | Zhu J.,Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction | Wang J.,Royal Dutch Shell | And 4 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

Based on the natural similarity between the parallel computing features of cellular automata and the parallel computing architecture of the CUDA, a dam-break flood routing computing model based on GPU-CA is proposed. Key technologies including cellular automata (CA) model of dam-break flood routing, GPU model mapping method, calculation optimization method, and GPU/CPU collaborative implementation for dam-break flood routing simulation and analysis are discussed in detail. Finally, a prototype system was developed and a case study region selected for carrying out a preliminary experiment. As compared to the CPU-CA model computing, the experimental results showed that the dam-break flood routing computing based on GPU-CA model can greatly improve the computing efficiency, and also ensured the validity of the simulation results. Speedup can be improved by increasing the cellular grid resolution. When the cellular grid size was 10 m, the speedup of model calculation reached 15.9 times, which can support real-time simulation analysis and risk assessment for dam-break flood routing. Source


Chen M.,Southwest Jiaotong University | Chen M.,Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction | Zhu Q.,Southwest Jiaotong University | Zhu J.,Southwest Jiaotong University | And 4 more authors.
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2016

A robust interest point detection algorithm based on illumination space and phase congruency is proposed in this paper. Firstly, image illumination space is constructed by using a parameters adaptive method. Secondly, a phase congruency based interest point detection algorithm is adopted to compute candidate points in illumination space. Then, all interest point candidates are mapped back to the original image and a non-maximum suppression step is added to find final interest points. Finally, the feature scale values of all interest points are calculated based on the Laplacian function. The proposed algorithm combines the advantages of illumination space and phase congruency, which makes the proposed method robust to the radiation variation of multispectral images. The experimental results show that the proposed method performs better than other traditional methods in feature repeatability rate and repeated features number. © 2016, Surveying and Mapping Press. All right reserved. Source


Chen M.,Southwest Jiaotong University | Chen M.,Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction | Zhu Q.,Southwest Jiaotong University | Zhu J.,Southwest Jiaotong University | And 4 more authors.
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2016

A matching method for SAR and optical images, robust to pixel noise and nonlinear grayscale differences, is presented. Firstly, a rough correction to eliminate rotation and scale change between images is performed. Secondly, features robust to speckle noise of SAR image are detected by improving the original phase congruency based method. Then, feature descriptors are constructed on the Gaussian-Gamma-shaped edge strength map according to the histogram of oriented gradient pattern. Finally, descriptor similarity and geometrical relationship are combined to constrain the matching processing. The experimental results demonstrate that the proposed method provides significant improvement in correct matches number and image registration accuracy compared with other traditional methods. © 2016, Surveying and Mapping Press. All right reserved. Source


Wei Y.,Zhengzhou University | Wei Y.,Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction | Ding Y.,Southwest Jiaotong University | Ding Y.,Chinese University of Hong Kong | And 3 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

The texture data plays an important role in three-dimensional topography simulation for virtual battlefield environment. 3D graphics engine such as OpenGL or D3D provides multi-texture mapping mechanism or shader, which is able to achieve the integration of multiple textures. But the achievement of multiple textures is GPU-based, which will take a large occupancy of GPU memory and bandwidth. In thin clients, such method will cause a lower render delay and lower efficiency. Therefore, a novel SSE2 based multi-texture blending method is presented in this paper, which implements the multiple textures blending process on CPU. The experiment proved that this method can effectively reduce the GPU load, achieve the integration of real-time multi-layered texture, and improve the rendering efficiency of three-dimensional topography simulation system. ©, 2015, Wuhan University. All right reserved. Source


Zeng C.,CAS Chengdu Institute of Mountain Hazards and Environment | Zeng C.,Sichuan Engineering Research Center for Emergency Mapping & Disaster Reduction | Su Z.-M.,CAS Chengdu Institute of Mountain Hazards and Environment | Lei Y.,CAS Chengdu Institute of Mountain Hazards and Environment | Yu J.,Chengdu University of Technology
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

A series of impact experiments were conducted on debris flow slurries and the mixtures of the debris flow slurry and large-sized particles with densities of 1400-2200 kg/m3, and 31 groups of impact experimental data at velocities of 2.4-5.2 m/s were obtained. The noise signals generated from device vibration and environmental interference are filtered out with the wavelet analysis method. Based on the results of the frequency spectral analysis using the fast Fourier transform method, a frequency threshold of 2 Hz is identified so that the low-frequency slurry impact force and the high-frequency large-sized particle impact force can be effectively separated. In the current hydrodynamic model the empirical coefficient α is generally difficult to determine. To resolve the issue, the functional dependence of the fluid Froude number Fr on coefficient α is developed based on 157 sets of debris flow monitoring data; and a formulation for calculating the slurry impact force is proposed, which represents different flow forms and the diminishing size effect. Compared to the smooth nature of slurry impact force, the large-sized particle impact force has more random characteristics. Both the number and frequency of particles impact on sensors increase when more particles are mixed in the flow. When mass ratio of particles increases from 0.05 to 0.21, the impact number increases from 1 305 to 2 838 times, and the impact frequency also increases from 82 to 195 times per second. The average particle impact force is about 60 kPa, which is about 3 times that of slurry. The frequency of particles detected by the upper sensors becomes larger than that detected by the bottom sensors as the particles content increases, demonstrating that the particles are prone to concentrate on the surface or at the head of debris. ©, 2015, Academia Sinica. All right reserved. Source

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