ISSN:0143-1161    

DOI:10.1080/01431169208904213

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

As part of a campaign organized by ESA and the Joint Research Centre Ispra, two sorties of the NASA DC-8 aircraft took place during August 1989 over three East Anglian test sites. The aircraft was equipped with the Jet Propulsion Laboratory P-/L-/C-band SAR and the characteristics of the radar are outlined and the associated calibration campaign described. An extensive ground data collection campaign was undertaken by a series of UK groups for forestry, agricultural and hydrological applications. The collection of forestry ground data is described in some detail. The anticipated uses of the ground data in the analysis of the radar images helped to determine the strategy for the selection of parameters to be measured.

ISSN:0143-1161    

DOI:10.1080/01431169208904214

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The geometry of Synthetic Aperature Radar (SAR) needs to be properly understood in order to match the images to a map or to extract topographic data. This paper concentrates on the distortions introduced into an image because of the relief of the ground and the way in which the topography can be extracted if two overlapping images are available. A mathematical model can be determined to describe a single image, and if a terrain model is available this can be used with the mathematical model to geocode the image. Information on the way in which the SAR data is recorded and processed is essential for producing a correct model. A number of methods have been developed and tested and these are described and assessed in the paper. Accurate geocoding is not possible without terrain data and if such data are not available, only corrections to allow for the ellipsoidal earth can be applied. A possible solution to this problem is to produce the elevation model from stereoscopic SAR or, if this is not possible, from a stereo pair made up of a SAR image and an image from another sensor such as SPOT. The geometric aspects of this are considered, together with some of the practical problems which may arise when working with stereo images of this type.

ISSN:0143-1161    

DOI:10.1080/01431169208904215

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The German Remote Sensing Data Centre (DFD) located at DLR in OberpfafTenhofen will be one of the primary European data centres for ERS-1 products. The two major systems of I his German Processing and Archiving Facility (D-PAF) comprise the generation of Altimeter and Orbit products and the SAR data product generation chain. The latter comprise the ISAR data processor and the SAR Geocoding System (GEOS). A brief description of the algorithms and subsystems of GEOS is given.

ISSN:0143-1161    

DOI:10.1080/01431169208904216

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Full-bandwidth C-band synthetic aperture radar (SAR) data are compared with 7-look and 3-look data. The peak-to-background ratio of the image intensity power spectrum describing the wave detectability is found to be on average 8-9dB higher for the 7-look data and 2-5dB higher for the 3-look data than the single-look data. This is mainly due to the decrease in the speckle noise level when going from single-look to multi-look processing. In addition, look-sum processing is evaluated against spectral-sum processing for various temporal look separations. A significant improvement in image spectral peak contrast is observed for the spectral-sum data versus the look-sum data, with increasing temporal separations between the looks. No such improvement is observed in the corresponding image spectral noise contrast parameter. These observations are in agreement with the spatial misregistration inherent in look-sum data. Finally, the acceleration contribution to the observed aximuth smearing in the spectra is found to be negligible compared with the velocity smearing contribution.

ISSN:0143-1161    

DOI:10.1080/01431169208904217

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The similarities and differences between imagery acquired at X-, C- and L-bands are examined by calculating the correlations between X-, C-, and L-band SAR data acquired over an agricultural area near Melfort, Saskatchewan in western Canada with the CCRS SAR-580. The SAR data were acquired on two separate occasions during the growing season (July and August, 1983) with vertical polarization in both transmit and receive.

ISSN:0143-1161    

DOI:10.1080/01431169208904218

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper summarizes the properties of the surface backscattering coefficient as a function of roughness, incidence angle, frequency and polarization state. Results are presented in the form of like- and cross-polarized backscattering coefficient curves versus the incidence angle and the polarization state for different values of the surface roughness parameters and frequency. It is seen that there is a gradual transition from the standard small perturbation scattering model into the Kirchhoff scattering model as frequency increases. It is also shown that in the intermediate frequency region neither the small perturbation nor the Kirchhoff model is applicable. The maximum value of the polarized backscattering coefficient occurs at VV polarization and its two minimum values occur at zero ellipticity and orientation angles between 0° and 45° and between 135° and 180°. The cross-polarized scattering coefficient has two maximum values which occur in the same polarization state regions as the minima of the polarized coefficients.

ISSN:0143-1161    

DOI:10.1080/01431169208904219

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The ground cover ratio of a partial covering early winter wheal crop at the 1 cm stem + spike stage has been evaluated using a three channels CIMEL radiometer which simulated the SPOT satellite observation bands. During short periods guaranteeing constant illumination, the reflectance of experimental plots was linearly correlated to the plants' ground cover ratio within a range of 0 and 57 per cent. This result was used to construct charts to allow the estimation of the ground cover ratio of a given area from reflectance measurements in the red and infrared bands.

ISSN:0143-1161    

DOI:10.1080/01431169208904220

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Information on actual land cover is necessary for various applications, such as soil and groundwater protection studies and hydrological studies. Therefore, a decision to produce a national land cover data base of the Netherlands, using satellite images, was made. The first version of the data base is now available for the whole of the Netherlands. Prior to the supervised classification the area was stratified in more or less homogeneous areas. Because cost, time and logistics required for a random sampling of the entire country were prohibitive, a mixed quantitative/qualitative classification accuracy assessment procedure was proposed. Classification performances were quantitatively assessed by comparing the classification results with digitized ground reference maps using a Geographical Information System (GIS). This offers a flexible method for locating the incorrectly labelled pixels and determining the possible reasons thereof. Classification accuracy of the land cover types which do not change much in time was also qualitatively assessed, using aerial photographs and topographical maps. The land cover data derived from remote sensing images can be readily combined with other digitized geographical data bases (e.g. soil maps).

ISSN:0143-1161    

DOI:10.1080/01431169208904221

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

For monitoring (homogeneous) agricultural crops, a quantitative analysis of aerial photography tends to favour black and white multi-spectral aerial photography. For monitoring natural vegetation on the other hand, a visual interpretation may be of primary importance, necessitating false colour photography. If an additional quantitative analysis of false colour photography is required, e.g. for biomass assessment, application of a red filter (FCR) provides a considerable simplification of the analysis, resulting in broad-band red and near-infrared reflectance factors. The reflectance factor in the near-infrared shows a decreased contrast compared with black and white multi-spectral aerial photography. In practical applications, this decrease in contrast with FCR has to be weighed against the possibilities of a visual interpretation.

ISSN:0143-1161    

DOI:10.1080/01431169208904222

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor