Since the atmospheric correction is a necessary preprocessing step of remote sensing image before detecting green tide, the introduced error directly affects the detection precision. Therefore, the detection method of...Since the atmospheric correction is a necessary preprocessing step of remote sensing image before detecting green tide, the introduced error directly affects the detection precision. Therefore, the detection method of green tide is presented from Landsat TM/ETM plus image which needs not the atmospheric correction. In order to achieve an automatic detection of green tide, a linear relationship（y =0.723 x＋0.504） between detection threshold y and subtraction x（x=λnir–λred） is found from the comparing Landsat TM/ETM plus image with the field surveys.Using this relationship, green tide patches can be detected automatically from Landsat TM/ETM plus image.Considering there is brightness difference between different regions in an image, the image will be divided into a plurality of windows（sub-images） with a same size firstly, and then each window will be detected using an adaptive detection threshold determined according to the discovered linear relationship. It is found that big errors will appear in some windows, such as those covered by clouds seriously. To solve this problem, the moving step k of windows is proposed to be less than the window width n. Using this mechanism, most pixels will be detected[n/k]×[n/k] times except the boundary pixels, then every pixel will be assigned the final class（green tide or sea water） according to majority rule voting strategy. It can be seen from the experiments, the proposed detection method using multi-windows and their adaptive thresholds can detect green tide from Landsat TM/ETM plus image automatically. Meanwhile, it avoids the reliance on the accurate atmospheric correction.展开更多
The commercial high-resolution imaging satellite with 1 m spatial resolution IKONOS is an important data source of information for urban planning and geographical information system (GIS) applications. In this paper, ...The commercial high-resolution imaging satellite with 1 m spatial resolution IKONOS is an important data source of information for urban planning and geographical information system (GIS) applications. In this paper, a morphological method is proposed. The proposed method combines the automatic thresholding and morphological operation techniques to extract the road centerline of the urban environment. This method intends to solve urban road centerline problems, vehicle, vegetation, building etc. Based on this morphological method, an object extractor is designed to extract road networks from highly remote sensing images. Some filters are applied in this experiment such as line reconstruction and region filling techniques to connect the disconnected road segments and remove the small redundant. Finally, the thinning algorithm is used to extract the road centerline. Experiments have been conducted on a high-resolution IKONOS and QuickBird images showing the efficiency of the proposed method.展开更多
Image registration is a kind of image processing that merges a series of pictures, any two neighbors having a common part, into one global image. Together with the feature extracting, the most difficult work in automa...Image registration is a kind of image processing that merges a series of pictures, any two neighbors having a common part, into one global image. Together with the feature extracting, the most difficult work in automatic registration is how to efficiently match the common feature information in different images. Based on the invariant property of affine transform, a centroid-based method of automatic feature matching is presented in this paper. Compared with the current state-of-the-art methods, the method in this paper is more efficient for the testing images, including MRI, CT, and satellite images. Another advantage of the method in this paper is that it has a linear computational complexity.展开更多
Under different conditions, the highest detection probability should be acquired while receiving laser echo during laser pulse range finding. The threshold voltage of the signal detection can be set corresponding ...Under different conditions, the highest detection probability should be acquired while receiving laser echo during laser pulse range finding. The threshold voltage of the signal detection can be set corresponding to different conditions by using resistor network. As a feedback loop, automatic noise threshold circuit could change the threshold voltage following the noise level. The threshold can track the noise closely, rapidly and accurately by adopting this combination. Therefore, the receiving capability of laser echo receiving system will be maximized, and it can detect weaker laser pulse from noise.展开更多
基金The National Natural Science Foundation of China under contract Nos 41506198 and 41476101the Natural Science Foundation Projects of Shandong Province of China under contract No.ZR2012FZ003the Science and Technology Development Plan of Qingdao City of China under contract No.13-1-4-121-jch
文摘Since the atmospheric correction is a necessary preprocessing step of remote sensing image before detecting green tide, the introduced error directly affects the detection precision. Therefore, the detection method of green tide is presented from Landsat TM/ETM plus image which needs not the atmospheric correction. In order to achieve an automatic detection of green tide, a linear relationship（y =0.723 x＋0.504） between detection threshold y and subtraction x（x=λnir–λred） is found from the comparing Landsat TM/ETM plus image with the field surveys.Using this relationship, green tide patches can be detected automatically from Landsat TM/ETM plus image.Considering there is brightness difference between different regions in an image, the image will be divided into a plurality of windows（sub-images） with a same size firstly, and then each window will be detected using an adaptive detection threshold determined according to the discovered linear relationship. It is found that big errors will appear in some windows, such as those covered by clouds seriously. To solve this problem, the moving step k of windows is proposed to be less than the window width n. Using this mechanism, most pixels will be detected[n/k]×[n/k] times except the boundary pixels, then every pixel will be assigned the final class（green tide or sea water） according to majority rule voting strategy. It can be seen from the experiments, the proposed detection method using multi-windows and their adaptive thresholds can detect green tide from Landsat TM/ETM plus image automatically. Meanwhile, it avoids the reliance on the accurate atmospheric correction.
文摘The commercial high-resolution imaging satellite with 1 m spatial resolution IKONOS is an important data source of information for urban planning and geographical information system (GIS) applications. In this paper, a morphological method is proposed. The proposed method combines the automatic thresholding and morphological operation techniques to extract the road centerline of the urban environment. This method intends to solve urban road centerline problems, vehicle, vegetation, building etc. Based on this morphological method, an object extractor is designed to extract road networks from highly remote sensing images. Some filters are applied in this experiment such as line reconstruction and region filling techniques to connect the disconnected road segments and remove the small redundant. Finally, the thinning algorithm is used to extract the road centerline. Experiments have been conducted on a high-resolution IKONOS and QuickBird images showing the efficiency of the proposed method.
基金Supported by the Special Scientific Research Program of the Education Department of Shaanxi Province(Grant No.18JK0161)the Scientific Research Foundation of Shaanxi University of Technology(Grant No.SLGQD1807)
文摘Image registration is a kind of image processing that merges a series of pictures, any two neighbors having a common part, into one global image. Together with the feature extracting, the most difficult work in automatic registration is how to efficiently match the common feature information in different images. Based on the invariant property of affine transform, a centroid-based method of automatic feature matching is presented in this paper. Compared with the current state-of-the-art methods, the method in this paper is more efficient for the testing images, including MRI, CT, and satellite images. Another advantage of the method in this paper is that it has a linear computational complexity.
文摘Under different conditions, the highest detection probability should be acquired while receiving laser echo during laser pulse range finding. The threshold voltage of the signal detection can be set corresponding to different conditions by using resistor network. As a feedback loop, automatic noise threshold circuit could change the threshold voltage following the noise level. The threshold can track the noise closely, rapidly and accurately by adopting this combination. Therefore, the receiving capability of laser echo receiving system will be maximized, and it can detect weaker laser pulse from noise.
