检索结果-内蒙古大学图书馆

IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Daniel L. Morstad Dennis L. Helder Image Processing Laboratory South Dakota State University SD USA Electrical Engineering and Computer Science Department South Dakota State University SD USA

Over the past several years, pseudo-invariant sites for trending the radiometric gain of multispectral satellite imaging systems has proven to be very useful and accurate. For example, the lifetime calibration of the Landsat 5 Thematic Mapper (TM) was recently updated based in large part upon this approach. This effort reduced the error in the gain estimate from roughly 13 percent to less than 5 percent and integrated a variety of absolute calibration estimates for the sensor. Typically, pseudo-invariant sites are located in arid regions where very little temporal and spatial change occurs over long periods of time and significant extent. Sites in the Sahara desert are especially attractive. However, drawbacks of this approach are that the sites are relatively unacceptable and, for some instruments, only limited numbers of data sets are available. As a result, it would be helpful to use sites that are observed often, such as locations in North America, so that the technique could be applied to more sensors both historically and in the future. The drawback to these sites is that they are typically of much smaller extent and, therefore, are more difficult to use from a geometric perspective. Recent work has shown that small pseudo-invariant sites, if carefully chosen, can also be used for accurate trending of satellite instruments. This paper will illustrate an approach that suggests the calibration site commonly known as Sonoran Desert can be used to observe the characteristic calibration curve of Landsat 5 TM. Because of the significant number of observations of this site, and other similar sites in North America, there is good potential to extend this technique to additional multispectral instruments for enhanced long term monitoring of radiometric gain.

关键词： Calibration remote sensing Radiometry Satellite broadcasting Instruments North America remote monitoring Uncertainty Layout Sun

来源：评论

学校读者我要写书评

暂无评论

Radiometric Calibration of Reflective Bands of Landsat 4 Thematic Mapper using Pseudo-Invariant Site Technique

Radiometric Calibration of Reflective Bands of Landsat 4 The...

引用

IEEE International Symposium on Geoscience and remote sensing (IGARSS)

作者： Rimy Malla Dennis L. Helder Image Processing Laboratory South Dakota State University SD USA Electrical Engineering and Computer Science Department South Dakota State University SD USA

Historically, for purposes of calibration, the Landsat 4 Thematic Mapper (TM) sensor has relied upon prelaunch calibration data, internal calibration data and very limited post-launch data. Landsat 4 additionally has used Landsat 5 TM cross-calibration data. The availability of one more independent source, commonly called pseudo-invariant sites, can be used to improve the calibration of the sensor. Pseudo-invariant sites are mainly well characterized desert sites exhibiting the properties of high reflectance, high spatial and spectral uniformity, temporal stability and are nearly Lambertian to decrease BRDF and shadow effects. The successful update of the calibration of the Landsat 5 TM sensor using the pseudo-invariant site approach suggested using this approach to calibrate the Landsat 4 TM sensor. The pseudo-invariant sites selected to characterize the Landsat 4 TM sensor are Middle East sites at Path 166, Row 39 and Path 166, Row 40. Previously, calibration attempts have been primarily based only on the internal calibrator (IC) and prelaunch data. The Landsat 5 internal calibrator was found to be unreliable approximately three years after launch. The Landsat 4 IC data also become questionable especially knowing that the internal calibrators for both the instruments were essentially identical. Thus, it is necessary to characterize the system with another independent and reliable source-in this case pseudo-invariant sites. Unfortunately, due to the unavailability of an adequate number of scenes at the site used for Landsat 5, the Middle East site of Path 166, Row 39 and Path 166, Row 40 were selected. A large drawback of these sites is that they are the locations of the First Gulf War in 1991. This negates the assumption that the surface and atmosphere did not change during the study period. To account for the change, radiometric correction was done using the known Landsat 5 gain signature. A correction factor, which is the ratio of the averages of Landsat 5 pre-g

关键词： Radiometry Calibration Satellites remote sensing Sensor phenomena and characterization Integrated circuit modeling Reflectivity Stability Instruments Layout

来源：评论

学校读者我要写书评

暂无评论

Fundamental Uncertainty Rotationally Symmetric and Anamorphic Laser Triangulation

引用

电子学报(英文版) 2008年第1期17卷 8-11页

作者： WANG Lei GAO Jun WANG Xiaojia Johannes Eckstein Peter Ott Laboratory of Image Information Processing School of Computer and Information Hefei University of Technology Hefei 230009 China Optical Engineering Laboratory Heilbronn University Heilbronn 74081 Germany Department of Mechanical and Electrical Engineering Xiamen University Xiamen 361005 China

来源：评论

学校读者我要写书评

暂无评论

A study on the effect of camera motion on human visual attention

A study on the effect of camera motion on human visual atten...

引用

IEEE International Conference on image processing

作者： Golnaz Abdollahian Zygmunt Pizlo Edward J. Delp Video and Image Processing Laboratory (VIPER) School of Electrical and Computer Engineering Purdue University West Lafayette IN USA Department of Psychological Sciences Purdue University West Lafayette IN USA

The aim of this paper is to examine the effect of camera motion in user generated video with respect to human visual attention. Having a more accurate human attention model is particularly useful in applications such as video summarization where the identification of visual importance is crucial to the quality of the results. Most models proposed thus far, have not considered camera motion as an independent factor in identifying visual saliency. In this study eye movement was recorded while subjects watched videos with different types of camera motion. The distribution of the fixation points indicated high correlation between the visual saliency and the type and direction of camera movement. The statistical tests confirmed that the results are statistically significant.

关键词： Cameras Humans Layout Testing Video sequences image processing Laboratories Psychology Information analysis Shape

来源：评论

学校读者我要写书评

暂无评论

A kidney segmentation approach from DCE-MRI using level sets

A kidney segmentation approach from DCE-MRI using level sets

引用

IEEE computer Society Conference on computer Vision and Pattern Recognition Workshops (CVPRW)

作者： H. Abdelmunim Aly A. Farag W. Miller Mohamed AboelGhar Department of Computer Science Computational Biomedicine Laboratory University of Houston Houston TX USA Computer Vision and Image Processing LabDepartment of Electrical and Computer Engineering University of Louisville Louisville KY USA Medical School Mansoura University Mansoura Egypt

Acute rejection is the most common reason of graft failure after kidney transplantation, and early detection is crucial to survive the transplanted kidney function. Automatic classification of normal and acute rejection transplants from dynamic contrast enhanced magnetic resonance imaging (DCEMRI), is of great importance. Kidney segmentation is the first step for such classification. The image intensity inside the kidney is used as an indication of failure/success. Differentiating between different cases cases is implemented by comparing subsequential kidney scans signals. So, this process is mainly dependent on segmentation. This paper introduces a new shape-based segmentation approach based on level sets. Training shapes are collected from different real data sets to represent the shape variations. Signed distance functions are used to represent these shapes. The methodology incorporates image and shape prior information in a variational framework. The shape registration is considered the backbone of the approach where more general transformations can be used to handle the process. We introduce a novel shape dissimilarity measure that enables the use of different (inhomogeneous) scales. The approach gives successful results compared with other techniques restricted to transformations with homogeneous scales. Results for segmenting kidney images will be illustrated and compared with other approaches to show the efficiency of the proposed technique.

关键词： Level set image segmentation computer vision Magnetic resonance imaging Shape measurement Biopsy Biomedical computing computer science image processing Biomedical imaging

来源：评论

学校读者我要写书评

暂无评论

A novel dual-frequency RF MEMS phase shifter

A novel dual-frequency RF MEMS phase shifter

引用

International Zurich Symposium on Electromagnetic Compatibility (EMC Zurich)

作者： Kai Tang Yu-ming Wu Qun Wu Hai-long Wang Huai-cheng Zhu Le-Wei Li Department of Electronic & Communications Engineering Harbin Institute of Technology Harbin China Department of Electrical and Computer Engineering National University of Singapore Singapore National Key Laboratory of Millimetre Wave System Institute of Remote Sensing Equipment Beijing China

The operating principle of the RF MEMS phase shifter is described. A novel design concept for dual-frequency RF MEMS phase shifter is proposed. By using network theory and CST microwave studio simulation tool, the proposed RF MEMS phase shifter is modelled. Simulation results show that the proposed model has the return loss less than -10dB and the insertion loss more than -2dB in two operating frequencies, both of which are more than 1 GHz bandwidth. For one RF MEMS phase shifter, both 180-degree and 90-degree phase shift are realized.

关键词： Radiofrequency microelectromechanical systems Phase shifters Bridge circuits Micromechanical devices Transmission line theory Capacitance Coplanar waveguides Insertion loss Transmission line matrix methods Frequency

来源：评论

学校读者我要写书评

暂无评论

4D wavelet noise suppression of MR diffusion tensor data

4D wavelet noise suppression of MR diffusion tensor data

引用

International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： Hesamoddin Jahanian Azadeh Yazdan-Shahmorad Hamid Soltanian-Zadeh Department of Radiology Henry Ford Health System Image Analysis and Communications Laboratory Detroit MI USA Department of Biomedical Engineering University of Michigan Ann Arbor MI USA Controll and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran Tehran Iran

Diffusion tensor imaging (DTI) is known to be promising for providing anatomical information about white-matter fiber bundles that cannot be obtained by other non-invasive in vivo imaging methods. However, its application is limited because of its low signal-to-noise ratio and significant imaging artifacts. To improve the accuracy of tissue structural and architectural characterization with diffusion tensor imaging 4D wavelet denoising technique is used to improve the signal to noise ratio (SNR) of diffusion tensor images. To evaluate the proposed method, a high SNR data set is built by repeating and averaging the data acquisition several times and is compared to the denoised data. Our results revealed that wavelets would effectively reduce the noise in DTI data with less blurring of tissue types, especially in the white matter. It would suggest that by using the 4D wavelet noise suppression, one could decrease the acquisition time and still have an acceptable SNR.

关键词： Tensile stress Diffusion tensor imaging Signal to noise ratio Noise reduction Magnetic noise Anisotropic magnetoresistance Eigenvalues and eigenfunctions In vivo Magnetic resonance imaging Wavelet analysis

来源：评论

学校读者我要写书评

暂无评论

Updated radiometric calibration for the Landsat-5 thematic mapper reflective bands

Updated radiometric calibration for the Landsat-5 thematic m...

引用

作者： Helder, Dennis L. Markham, Brian L. Thome, Kurtis J. Barsi, Julia A. Chander, Gyanesh Malla, Rimy Department of Electrical Engineering and Computer Science South Dakota State University Brookings SD 57007 United States Landsat Project Science Office NASA Goddard Space Flight Center Greenbelt MD 20771 United States Remote Sensing Group Optical Sciences Center University of Arizona Tucson AZ 85721 United States Science Systems and Applications Inc. NASA Goddard Space Flight Center Greenbelt MD 20771 United States Science Applications International Corporation U.S. Geological Survey Center for Earth Resources Observation and Science Sioux Falls SD 57198 United States Image Processing Laboratory South Dakota State University Brookings SD 57007 United States

The Landsat-5 Thematic Mapper (TM) has been the workhorse of the Landsat system. Launched in 1984, it continues collecting data through the time frame of this paper. Thus, it provides an invaluable link to the past history of the land features of the Earth's surface, and it becomes imperative to provide an accurate radiometric calibration of the reflective bands to the user community. Previous calibration has been based on information obtained from prelaunch, the onboard calibrator, vicarious calibration attempts, and cross-calibration with Landsat-7. Currently, additional data sources are available to improve this calibration. Specifically, improvements in vicarious calibration methods and development of the use of pseudoinvariant sites for trending provide two additional independent calibration sources. The use of these additional estimates has resulted in a consistent calibration approach that ties together all of the available calibration data sources. Results from this analysis indicate a simple exponential, or a constant model may be used for all bands throughout the lifetime of Landsat-5 TM. Where previously time constants for the exponential models were approximately one year, the updated model has significantly longer time constants in bands 1-3. In contrast, bands 4, 5, and 7 are shown to be best modeled by a constant. The models proposed in this paper indicate calibration knowledge of 5% or better early in life, decreasing to nearly 2% later in life. These models have been implemented at the U.S. Geological Survey Earth Resources Observation and Science (EROS) and are the default calibration used for all Landsat TM data now distributed through EROS. © 2008 IEEE.

关键词： Landsat

来源：评论

学校读者我要写书评

暂无评论

Feature fusion as a practical solution toward noncooperative iris recognition

Feature fusion as a practical solution toward noncooperative...

引用

International Conference on Information Fusion

作者： Nima Tajbakhsh Babak N. Araabi Hamid Soltanianzadeh Control & Intelligent Processing Center of Excellence School of Electrical & Computer Engineering University of Tehran Tehran Iran School of Cognitive Sciences Institute of Studies in Theoretical Physics and Mathematics Tehran Iran Image Analysis Laboratory Radiology Department Henry Ford Health System Detroit MI USA

In noncooperative Iris recognition one should deal with uncontrolled behavior of the subject as well as uncontrolled lighting conditions. That means imperfect focus, contrast, brightness, and orientation among the others. To cope with this situation we propose to take iris images at both near infrared (NIR) and visible light (VL) and use them simultaneously for recognition. In this paper, a novel approach for iris recognition is proposed so that extracted features of NIR and VL images are fused to improve the recognition rate. When the images do not have enough quality due to focus, contrast, etc., effects of feature fusion is more pronounced. This is the situation in UTIRIS database, which is used in our experiments. Experimental results show that the proposed approach, especially in small training samples, leads to a remarkable improvement on recognition rate compared with either NIR or VL recognition.

关键词： Iris Feature extraction Discrete cosine transforms image recognition Databases Training Humans

来源：评论

学校读者我要写书评

暂无评论

Towards an inclusive computational model of visual cortex

Towards an inclusive computational model of visual cortex

引用

IEEE Symposium on Bioinformatics and Bioengineering (BIBE)

作者： M. Gheiratmand H. Soltanian-Zadeh H. Khaloozadeh Electrical Engineering Department K.N. Toosi University of Technology Tehran Iran Radiology Department Henry Ford Health System Image Analysis and Communications Laboratory Detroit MI USA School of Cognitive Sciences Institute for Studies Theoretical Physics and Mathematics (IPM) Tehran Iran Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department University of Tehran Tehran Iran

Understanding the primatespsila visual system has been one of the challenging problems of different groups of scientists for years. Though many studies, from physiology and neuroscience to computer vision, are done on different aspects of visual processing in the cortex, a comprehensive computational model of visual cortex is still missing. We have implemented a computational model of object recognition in ventral visual pathway in our previous work. This hierarchical model covers visual areas V1/V2, V4/PIT, and AIT sending inputs to the Prefrontal Cortex (PFC) for categorization. To extend our model, in this work, we have added a simple model of motion detection in neurons of areas V1 and MT of the dorsal stream to our previous model. This has enabled the model to perform another principal function of the visual cortex, i.e., motion perception.

关键词： Brain modeling Computational modeling Neurons Biological system modeling Object recognition Motion analysis Solid modeling Visual system computer vision Motion detection

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：