Detecting the moving vehicles in jittering traffic scenes is a very difficult problem because of the complex environment.Only by the color features of the pixel or only by the texture features of image cannot establis...Detecting the moving vehicles in jittering traffic scenes is a very difficult problem because of the complex environment.Only by the color features of the pixel or only by the texture features of image cannot establish a suitable background model for the moving vehicles. In order to solve this problem, the Gaussian pyramid layered algorithm is proposed, combining with the advantages of the Codebook algorithm and the Local binary patterns(LBP) algorithm. Firstly, the image pyramid is established to eliminate the noises generated by the camera shake. Then, codebook model and LBP model are constructed on the low-resolution level and the high-resolution level of Gaussian pyramid, respectively. At last, the final test results are obtained through a set of operations according to the spatial relations of pixels. The experimental results show that this algorithm can not only eliminate the noises effectively, but also save the calculating time with high detection sensitivity and high detection accuracy.展开更多
In recent years, the pressure of increasing coastal industries and tourism activities has, in some areas, led to the clearing of many coastal habitats along the Qatar＇s shorelines for the construction of tourist reso...In recent years, the pressure of increasing coastal industries and tourism activities has, in some areas, led to the clearing of many coastal habitats along the Qatar＇s shorelines for the construction of tourist resorts, tourism-related development and industrial facilities. Such threats are leading to the increasing demand for detailed mangrove maps for the purpose of measuring the extent of decline in mangrove ecosystems. Detailed mangrove maps at the community or species level are, however, not easy to produce, mainly because mangrove forests are very difficult to access. Without doubt, remote sensing is a serious alternative to traditional field-based methods for mangrove mapping, as it allows information to be gathered from the forbidding environment of mangrove forests, which otherwise, logistically and practically speaking, would be extremely difficult to survey. Remote sensing applications for mangrove mapping at the fundamental level are already well established but, surprisingly, a number of advanced remote sensing applications have remained unexplored for the purpose of mangrove mapping at a finer level. Consequently, the aim of this paper is to unveil the potential of some of the unexplored remote sensing techniques for mangrove studies. Temporal Landsat TM image of 1986, Landsat ETM image of 2000 and Resourcesat-1 LISS 3 image of 2008 are used to calculate percentage change in mangrove cover at AI Dhakira site using geometrically registered and radiometrically corrected historical Landsat and Resourcesat-1 images. Region masks are employed to isolate the unwanted area from the images. NDVI （normalized difference vegetation index） is used to detect mangroves using near-infrared and red bands which are computed from the satellite images. The ground-truthing visit to AI Dhakira site is conducted to confirm the results of the analysis. Change detection is applied and mangrove in the study area is found to have decreased by about 8.79% from 2000 to 2008.展开更多
In this paper,a technique based on image pyramid and Bayes rule for reducing noise effects in unsupervised change detection is proposed.By using Gaussian pyramid to process two multitemporal images respectively,two im...In this paper,a technique based on image pyramid and Bayes rule for reducing noise effects in unsupervised change detection is proposed.By using Gaussian pyramid to process two multitemporal images respectively,two image pyramids are constructed.The difference pyramid images are obtained by point-by-point subtraction between the same level images of the two image pyramids.By resizing all difference pyramid images to the size of the original multitemporal image and then making product operator among them,a map being similar to the difference image is obtained.The difference image is generated by point-by-point subtraction between the two multitemporal images directly.At last,the Bayes rule is used to distinguish the changed pixels.Both synthetic and real data sets are used to evaluate the performance of the proposed technique.Experimental results show that the map from the proposed technique is more robust to noise than the difference image.展开更多
The detailed structures of the volcanic edifice and plumbing system of the early Permian Tarim flood basalt were investigated by three-dimensional seismic imaging. The images show that the Tarim flood basalt erupted f...The detailed structures of the volcanic edifice and plumbing system of the early Permian Tarim flood basalt were investigated by three-dimensional seismic imaging. The images show that the Tarim flood basalt erupted from central volcanoes distributed along major faults. The uppermost magma formed a single lava lobe with a volume of *0.74 km3 and an aspect ratio of 50,implying a sheet flow eruption with a high effusion rate. At the subsurface level, all central volcanoes, irrespective of size, had a separate pipe-like feeder vent. Only thirteen dikes were identified at shallow depths of \100 m below the lava surface; deeper dikes were even rarer. The pipelike plumbing system and the paucity of dilational dikes were different from the typical plumbing system of flood basalt provinces on Earth, which are normally buoyancycontrolled dike–sill networks. A gas-driven vigorous eruption can be inferred from the imaged structure, which means that the Tarim flood basalt may have carried and released a large proportion of volcanic gas, similar to some mafic volcaniclastic deposit-bearing continental flood basalt provinces.展开更多
A novel method for multi-image matching by synthesizing image and object-space information is proposed. Firstly, four levels of image pyramids are generated according to the rule that the next pyramid level is generat...A novel method for multi-image matching by synthesizing image and object-space information is proposed. Firstly, four levels of image pyramids are generated according to the rule that the next pyramid level is generated from the previous level using the average gray values of the 3 by 3 pixels, and the first level of pyramid image is generated from the original image. The initial horizontal parallaxes between the reference image and each searching image are calculated at the highest level of the image pyramid. Secondly, corresponding image points are searched in each stereo image pair from the third level of image pyramid, and the matching results in all stereo pairs are integrated in the object space, by which the mismatched image points can be eliminated and more accurate spatial information can be obtained for the subsequent pyramid image matching. The matching method based on correlation coefficient with geometric constraints and global relaxation matching is introduced in the process of image matching. Finally, the feasibility of the method proposed in this paper is verified by the experiments using a set of digital frame aerial images with big overlap. Compared with the traditional image matching method with two images, the accuracy of the digital surface model (DSM) generated using the proposed method shows that the multiimage matching method can eliminate the mismatched points effectively and can improve the matching success rate significantly.展开更多
基金Project(61172047)supported by the National Natural Science Foundation of China
文摘Detecting the moving vehicles in jittering traffic scenes is a very difficult problem because of the complex environment.Only by the color features of the pixel or only by the texture features of image cannot establish a suitable background model for the moving vehicles. In order to solve this problem, the Gaussian pyramid layered algorithm is proposed, combining with the advantages of the Codebook algorithm and the Local binary patterns(LBP) algorithm. Firstly, the image pyramid is established to eliminate the noises generated by the camera shake. Then, codebook model and LBP model are constructed on the low-resolution level and the high-resolution level of Gaussian pyramid, respectively. At last, the final test results are obtained through a set of operations according to the spatial relations of pixels. The experimental results show that this algorithm can not only eliminate the noises effectively, but also save the calculating time with high detection sensitivity and high detection accuracy.
文摘In recent years, the pressure of increasing coastal industries and tourism activities has, in some areas, led to the clearing of many coastal habitats along the Qatar＇s shorelines for the construction of tourist resorts, tourism-related development and industrial facilities. Such threats are leading to the increasing demand for detailed mangrove maps for the purpose of measuring the extent of decline in mangrove ecosystems. Detailed mangrove maps at the community or species level are, however, not easy to produce, mainly because mangrove forests are very difficult to access. Without doubt, remote sensing is a serious alternative to traditional field-based methods for mangrove mapping, as it allows information to be gathered from the forbidding environment of mangrove forests, which otherwise, logistically and practically speaking, would be extremely difficult to survey. Remote sensing applications for mangrove mapping at the fundamental level are already well established but, surprisingly, a number of advanced remote sensing applications have remained unexplored for the purpose of mangrove mapping at a finer level. Consequently, the aim of this paper is to unveil the potential of some of the unexplored remote sensing techniques for mangrove studies. Temporal Landsat TM image of 1986, Landsat ETM image of 2000 and Resourcesat-1 LISS 3 image of 2008 are used to calculate percentage change in mangrove cover at AI Dhakira site using geometrically registered and radiometrically corrected historical Landsat and Resourcesat-1 images. Region masks are employed to isolate the unwanted area from the images. NDVI （normalized difference vegetation index） is used to detect mangroves using near-infrared and red bands which are computed from the satellite images. The ground-truthing visit to AI Dhakira site is conducted to confirm the results of the analysis. Change detection is applied and mangrove in the study area is found to have decreased by about 8.79% from 2000 to 2008.
基金the National Basic Research Program(973) of China (No. 2006CB701303)the National High Technology Research and Development Program(863) of China (No. 2006AA12Z105)
文摘In this paper,a technique based on image pyramid and Bayes rule for reducing noise effects in unsupervised change detection is proposed.By using Gaussian pyramid to process two multitemporal images respectively,two image pyramids are constructed.The difference pyramid images are obtained by point-by-point subtraction between the same level images of the two image pyramids.By resizing all difference pyramid images to the size of the original multitemporal image and then making product operator among them,a map being similar to the difference image is obtained.The difference image is generated by point-by-point subtraction between the two multitemporal images directly.At last,the Bayes rule is used to distinguish the changed pixels.Both synthetic and real data sets are used to evaluate the performance of the proposed technique.Experimental results show that the map from the proposed technique is more robust to noise than the difference image.
基金supported by the National Basic Research Program of China(2010CB808906)the National Natural Science Foundation of China(41272368)to WT
文摘The detailed structures of the volcanic edifice and plumbing system of the early Permian Tarim flood basalt were investigated by three-dimensional seismic imaging. The images show that the Tarim flood basalt erupted from central volcanoes distributed along major faults. The uppermost magma formed a single lava lobe with a volume of *0.74 km3 and an aspect ratio of 50,implying a sheet flow eruption with a high effusion rate. At the subsurface level, all central volcanoes, irrespective of size, had a separate pipe-like feeder vent. Only thirteen dikes were identified at shallow depths of \100 m below the lava surface; deeper dikes were even rarer. The pipelike plumbing system and the paucity of dilational dikes were different from the typical plumbing system of flood basalt provinces on Earth, which are normally buoyancycontrolled dike–sill networks. A gas-driven vigorous eruption can be inferred from the imaged structure, which means that the Tarim flood basalt may have carried and released a large proportion of volcanic gas, similar to some mafic volcaniclastic deposit-bearing continental flood basalt provinces.
基金Supported by the National Natural Science Foundation of China (Nos. 40771176, 40721001)
文摘A novel method for multi-image matching by synthesizing image and object-space information is proposed. Firstly, four levels of image pyramids are generated according to the rule that the next pyramid level is generated from the previous level using the average gray values of the 3 by 3 pixels, and the first level of pyramid image is generated from the original image. The initial horizontal parallaxes between the reference image and each searching image are calculated at the highest level of the image pyramid. Secondly, corresponding image points are searched in each stereo image pair from the third level of image pyramid, and the matching results in all stereo pairs are integrated in the object space, by which the mismatched image points can be eliminated and more accurate spatial information can be obtained for the subsequent pyramid image matching. The matching method based on correlation coefficient with geometric constraints and global relaxation matching is introduced in the process of image matching. Finally, the feasibility of the method proposed in this paper is verified by the experiments using a set of digital frame aerial images with big overlap. Compared with the traditional image matching method with two images, the accuracy of the digital surface model (DSM) generated using the proposed method shows that the multiimage matching method can eliminate the mismatched points effectively and can improve the matching success rate significantly.
