Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.606394
D. Kasilingam, Jian Shi
An artificial neural network (ANN) based nonlinear technique for inverting the SAR image spectrum of ocean surface waves is developed. In this technique, a multi-layer perceptron (MLP) is used to perform the inversion process. The MLP is trained using simulated SAR and wave spectra. The training process utilizes the standard error-backpropagation technique. The results indicate that the method works well over a large range of wind and wave conditions. The error in the inversion process was found to increase in the higher sea states. The technique works best if the network is used within the range over which it was trained. It is noted that this technique may be used independent of SAR imaging models, by training the network with coincident and co-located measurements of SAR and wave spectra.
{"title":"Artificial neural network-based inversion technique for extracting ocean surface wave spectra from SAR images","authors":"D. Kasilingam, Jian Shi","doi":"10.1109/IGARSS.1997.606394","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.606394","url":null,"abstract":"An artificial neural network (ANN) based nonlinear technique for inverting the SAR image spectrum of ocean surface waves is developed. In this technique, a multi-layer perceptron (MLP) is used to perform the inversion process. The MLP is trained using simulated SAR and wave spectra. The training process utilizes the standard error-backpropagation technique. The results indicate that the method works well over a large range of wind and wave conditions. The error in the inversion process was found to increase in the higher sea states. The technique works best if the network is used within the range over which it was trained. It is noted that this technique may be used independent of SAR imaging models, by training the network with coincident and co-located measurements of SAR and wave spectra.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"118 1","pages":"1193-1195 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82441146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615894
Xu Ke, Li Mao-tang, Z. Ning, Xue Yonglin, Liu Yuesheng
An airborne radar altimeter (ARA) was developed in China in 1995. The airborne radar altimeter control system (ARACS) is discussed. The ARACS consists of an industrial control computer (ICC), controller and data sampling system (DSS). Besides controlling and managing the ARA, the ICC has charge of the ARA calibration, acquisition, tracking and data processing. The controller has the functions of controlling the microwave switches, generating chirp controlling signals and other controlling signals. The DSS has the functions of sampling and holding data. The ARA software consists of initialization, noise, bias, calibration, acquisition and tracking program elements. After being developed the ARA was tested in QingDao and satisfactory success was obtained.
{"title":"The China airborne radar altimeter control system","authors":"Xu Ke, Li Mao-tang, Z. Ning, Xue Yonglin, Liu Yuesheng","doi":"10.1109/IGARSS.1997.615894","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615894","url":null,"abstract":"An airborne radar altimeter (ARA) was developed in China in 1995. The airborne radar altimeter control system (ARACS) is discussed. The ARACS consists of an industrial control computer (ICC), controller and data sampling system (DSS). Besides controlling and managing the ARA, the ICC has charge of the ARA calibration, acquisition, tracking and data processing. The controller has the functions of controlling the microwave switches, generating chirp controlling signals and other controlling signals. The DSS has the functions of sampling and holding data. The ARA software consists of initialization, noise, bias, calibration, acquisition and tracking program elements. After being developed the ARA was tested in QingDao and satisfactory success was obtained.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"25 1","pages":"389-391 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82596871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615223
Liu Zhen, Li Shukai
The topographic effect and radiation effect are two key elements which affect the accuracy of classification of the remote sensing image. Topographical normalization is a valuable tool by use of DEM. Because the time when the image is acquired differs from that of DEM, a new error was induced in the procedure of topographical normalization. It is obvious that the image classification and DEM accuracies can be improved by use of the same spatial temporal and spatial resolution image and DEM. The DEM help radiation correction, on the other hand, the image provide some information on Earth objects to restore DEM. A new system was developed, which can provide highly accurate DEM and remote sensing image synchronously.
{"title":"Infusion of altimeter data to same spatial, temporal resolution infrared images to improve the accuracy of the classification of images and DEM","authors":"Liu Zhen, Li Shukai","doi":"10.1109/IGARSS.1997.615223","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615223","url":null,"abstract":"The topographic effect and radiation effect are two key elements which affect the accuracy of classification of the remote sensing image. Topographical normalization is a valuable tool by use of DEM. Because the time when the image is acquired differs from that of DEM, a new error was induced in the procedure of topographical normalization. It is obvious that the image classification and DEM accuracies can be improved by use of the same spatial temporal and spatial resolution image and DEM. The DEM help radiation correction, on the other hand, the image provide some information on Earth objects to restore DEM. A new system was developed, which can provide highly accurate DEM and remote sensing image synchronously.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"23 1","pages":"683-684 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82059650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615214
A. Marazzi, P. Gamba, A. Mecocci, E. Costamagna
One of the problems encountered in the field of remote sensing image characterization, is the choice for the right features. The addition of textures as a discriminating parameter is a good help in the step of segmentation of different zones. The authors present an approach that is a mix between a wavelet multiscale analysis and a fractal characterization, in order to exploit both the main characteristic of the two approaches and to override the limitations of the two techniques. The chain was applied to different textured images showing an improvement respect to other methods based on wavelet transform and fractal approach alone.
{"title":"A mixed fractal/wavelet based approach for characterization of textured remote sensing images","authors":"A. Marazzi, P. Gamba, A. Mecocci, E. Costamagna","doi":"10.1109/IGARSS.1997.615214","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615214","url":null,"abstract":"One of the problems encountered in the field of remote sensing image characterization, is the choice for the right features. The addition of textures as a discriminating parameter is a good help in the step of segmentation of different zones. The authors present an approach that is a mix between a wavelet multiscale analysis and a fractal characterization, in order to exploit both the main characteristic of the two approaches and to override the limitations of the two techniques. The chain was applied to different textured images showing an improvement respect to other methods based on wavelet transform and fractal approach alone.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"27 1","pages":"655-657 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82422089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615276
S. Sivaprakash, Junjie Ng, N. L. Teo, V. Khoo, Soo Chin Liew
The objective of this project is to create a compilation of educational resources in remote sensing accessible through the World-Wide Web (WWW). This compilation will be useful to anyone interested in learning about remote sensing. Educators might also find it useful as a place to locate useful resources for teaching courses in remote sensing. The remote sensing web resources were organized into several categories in the authors' web pages. These categories include: (1) Remote Sensing Missions, (2) Remote Sensing Applications, (3) Notes on Remote Sensing and (4) Interesting Images. The authors hope to provide a one-stop web page for accessing educational resources in remote sensing on the World Wide Web.
{"title":"Remote sensing education resources on the World Wide Web","authors":"S. Sivaprakash, Junjie Ng, N. L. Teo, V. Khoo, Soo Chin Liew","doi":"10.1109/IGARSS.1997.615276","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615276","url":null,"abstract":"The objective of this project is to create a compilation of educational resources in remote sensing accessible through the World-Wide Web (WWW). This compilation will be useful to anyone interested in learning about remote sensing. Educators might also find it useful as a place to locate useful resources for teaching courses in remote sensing. The remote sensing web resources were organized into several categories in the authors' web pages. These categories include: (1) Remote Sensing Missions, (2) Remote Sensing Applications, (3) Notes on Remote Sensing and (4) Interesting Images. The authors hope to provide a one-stop web page for accessing educational resources in remote sensing on the World Wide Web.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"2 1","pages":"848-849 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87465459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.609126
M. Simard, G. D. De Grandi, S. Saatchi, M. Leysen, K. Thomson
A new avenue for radar mapping of the tropical forest at continental scale was recently proposed in the context of the European TREES (TRopical Ecosystem Environment monitoring by Satellites) project. The related issues ask for suitable approaches in the processing and analysis phases, which are the main focus of this paper. Some engineering aspects of the processing chain are described. Next the problem of information extraction from the mosaic with respect to the TREES thematic objectives is tackled. A first research topic is the ability to extract multi-scale structures of the tropical forest. The analysis was done using a technique based on the wavelet transform.
{"title":"Processing and analysis techniques for continental scale radar maps of the tropical forest","authors":"M. Simard, G. D. De Grandi, S. Saatchi, M. Leysen, K. Thomson","doi":"10.1109/IGARSS.1997.609126","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.609126","url":null,"abstract":"A new avenue for radar mapping of the tropical forest at continental scale was recently proposed in the context of the European TREES (TRopical Ecosystem Environment monitoring by Satellites) project. The related issues ask for suitable approaches in the processing and analysis phases, which are the main focus of this paper. Some engineering aspects of the processing chain are described. Next the problem of information extraction from the mosaic with respect to the TREES thematic objectives is tackled. A first research topic is the ability to extract multi-scale structures of the tropical forest. The analysis was done using a technique based on the wavelet transform.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"78 1","pages":"1890-1892 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87838735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615892
B. Petrenko
A technique is described which embodies a robust approach to enhancing spatial resolution of aerospace images based on images made with another sensor with a better spatial resolution. The technique does not require an exact knowledge of the sensor angular functions replacing it with the analysis of a local signals spatial structure. The extent of correction of a low resolution image depends on its correlation with high resolution images. The universality of the technique is demonstrated by its applications to data of microwave and optical sensors.
{"title":"The universal multichannel technique for enhancing images obtained from different sensors","authors":"B. Petrenko","doi":"10.1109/IGARSS.1997.615892","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615892","url":null,"abstract":"A technique is described which embodies a robust approach to enhancing spatial resolution of aerospace images based on images made with another sensor with a better spatial resolution. The technique does not require an exact knowledge of the sensor angular functions replacing it with the analysis of a local signals spatial structure. The extent of correction of a low resolution image depends on its correlation with high resolution images. The universality of the technique is demonstrated by its applications to data of microwave and optical sensors.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"15 1","pages":"383-385 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87761413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.615289
B. Forster, C. Ticehurst, Y. Dong
The output from regular mapping and monitoring of urban areas provides an important source of information for urban planners and decision makers. The use of remotely sensed data to provide this information has been successful in particular environments but has had only limited success in tropical zone countries where cloud and rain often restrict the useful acquisition of visible/infrared image data on a regular basis. In many cases, and particularly in east Asia, these are precisely the areas that most need the data. A number of researchers have examined the potential of using radar images to overcome these problems, because at the wavelengths used (X- to P-), radar is not affected by cloud or rain. Urban areas are a spatially complex mixture of both natural and built surfaces whose spectral and geometric properties are many and varied. Buildings for example, cause significant backscatter when irradiated by microwave radiation, which is dependent on wavelength, polarisation and incidence angle of the radar beam, and roughness, dielectric properties and size, shape and orientation of the buildings and their surface facets. To some extent all combinations of specular and diffuse backscatter are a function of the height and width of buildings, and thus give rise to the possibility of using backscatter as a measure of the bulk density of the built environment. Equations for backscattering mechanisms, often found in urban environments, are well known. These are for example, facets, point scatterers, dihedral and trihedral corner reflectors, cylinders and wedges. This paper examines the theoretical relationships between urban morphology and remote sensing response at radar wavelengths, provides some preliminary results on measures of urban classification using AirSAR quad polarised radar data from test sites over the city of Sydney, Australia, and proposes a solution to the problem of backscatter variation due to building orientation.
{"title":"Analysis of radar response from urban areas","authors":"B. Forster, C. Ticehurst, Y. Dong","doi":"10.1109/IGARSS.1997.615289","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.615289","url":null,"abstract":"The output from regular mapping and monitoring of urban areas provides an important source of information for urban planners and decision makers. The use of remotely sensed data to provide this information has been successful in particular environments but has had only limited success in tropical zone countries where cloud and rain often restrict the useful acquisition of visible/infrared image data on a regular basis. In many cases, and particularly in east Asia, these are precisely the areas that most need the data. A number of researchers have examined the potential of using radar images to overcome these problems, because at the wavelengths used (X- to P-), radar is not affected by cloud or rain. Urban areas are a spatially complex mixture of both natural and built surfaces whose spectral and geometric properties are many and varied. Buildings for example, cause significant backscatter when irradiated by microwave radiation, which is dependent on wavelength, polarisation and incidence angle of the radar beam, and roughness, dielectric properties and size, shape and orientation of the buildings and their surface facets. To some extent all combinations of specular and diffuse backscatter are a function of the height and width of buildings, and thus give rise to the possibility of using backscatter as a measure of the bulk density of the built environment. Equations for backscattering mechanisms, often found in urban environments, are well known. These are for example, facets, point scatterers, dihedral and trihedral corner reflectors, cylinders and wedges. This paper examines the theoretical relationships between urban morphology and remote sensing response at radar wavelengths, provides some preliminary results on measures of urban classification using AirSAR quad polarised radar data from test sites over the city of Sydney, Australia, and proposes a solution to the problem of backscatter variation due to building orientation.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"1045 1","pages":"891-894 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86469496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.608906
W. Wynn
The five independent equations describing the field gradient tensor at a point for a static magnetic dipole source can be inverted to give the bearing vector to the source and the source moment vector divided by the fourth power of the range. The equations have four solutions, two of which are related in a non-trivial way, and two more that are obtained by reflections through the field point. The symmetry of the four solutions in the principal-axis frame of the gradient tensor can be used to express the solutions directly in terms of one another in an arbitrary frame without executing the inversion. This relationship has been exploited to construct explicit proofs that a unique solution for magnetic moment vector and relative position between source and field point can be obtained if either the magnetic field vector, or the rate of change of the gradient tensor and the relative motion of source and field point is known.
{"title":"Magnetic dipole localization with a gradiometer: obtaining unique solutions","authors":"W. Wynn","doi":"10.1109/IGARSS.1997.608906","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.608906","url":null,"abstract":"The five independent equations describing the field gradient tensor at a point for a static magnetic dipole source can be inverted to give the bearing vector to the source and the source moment vector divided by the fourth power of the range. The equations have four solutions, two of which are related in a non-trivial way, and two more that are obtained by reflections through the field point. The symmetry of the four solutions in the principal-axis frame of the gradient tensor can be used to express the solutions directly in terms of one another in an arbitrary frame without executing the inversion. This relationship has been exploited to construct explicit proofs that a unique solution for magnetic moment vector and relative position between source and field point can be obtained if either the magnetic field vector, or the rate of change of the gradient tensor and the relative motion of source and field point is known.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"64 1","pages":"1483-1485 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86201125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-03DOI: 10.1109/IGARSS.1997.606437
R. Romeiser
Multi-polarization radar images of the ocean surface from various experimental campaigns suggest that the backscattered signal is more sensitive to wind field variations at vertical (VV) than at horizontal (HH) polarization. On the other hand, radar signatures of oceanic features like internal waves or underwater bottom topography are often better visible at HH. In this paper, a possible theoretical explanation for these phenomena is discussed. It is shown that polarization-dependent radar signatures are qualitatively consistent with predictions of a composite surface scattering model, where the ratio between modulation depths at HH and VV is determined by the intensity variations of ocean waves in different wave-number ranges. Using a simple scenario of wind and current variations, it is demonstrated that a pair of radar images with dominant oceanic and atmospheric signatures at HH and VV, respectively, can be basically obtained from the model.
{"title":"On the polarization-dependent signatures of atmospheric and oceanic features in radar images of the ocean surface","authors":"R. Romeiser","doi":"10.1109/IGARSS.1997.606437","DOIUrl":"https://doi.org/10.1109/IGARSS.1997.606437","url":null,"abstract":"Multi-polarization radar images of the ocean surface from various experimental campaigns suggest that the backscattered signal is more sensitive to wind field variations at vertical (VV) than at horizontal (HH) polarization. On the other hand, radar signatures of oceanic features like internal waves or underwater bottom topography are often better visible at HH. In this paper, a possible theoretical explanation for these phenomena is discussed. It is shown that polarization-dependent radar signatures are qualitatively consistent with predictions of a composite surface scattering model, where the ratio between modulation depths at HH and VV is determined by the intensity variations of ocean waves in different wave-number ranges. Using a simple scenario of wind and current variations, it is demonstrated that a pair of radar images with dominant oceanic and atmospheric signatures at HH and VV, respectively, can be basically obtained from the model.","PeriodicalId":64877,"journal":{"name":"遥感信息","volume":"29 1","pages":"1326-1328 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1997-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86712045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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