ISSN:0143-1161    

DOI:10.1080/01431168608954657

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The question of an international regime for the regulation of remotesensing activities has been under active consideration for a number of years. The main problems that seem to preclude agreement at the United Nations seem to be national security, sovereignty and commercial considerations of the developed and developing countries. The main issues on this relate to the ‘right to sense’ and ‘the right to disseminate’ the data obtained from sensing. The underlying reasons why these are outstanding issues (even though they are never openly stated) are the ‘sensitivity aspects’ of remote sensing. In the 1980sthis complex problem is bound to be further complicated due to higher resolution, commercialization and the increase in the number of countries launching remote-sensing satellites. A critical analysis of existing international law seems to indicate that there are two kinds of remote sensing–active sensing and passive sensing. While in a strict legal sense passive sensing may be construed as legitimate the rules for active sensing are not that clear. Agreement on remote sensing can be reached if a resolution or a range of resolutions can be identified to distinguish ‘sensitive’ from ‘non-sensitive’ data. The only international agreement on remote sensing is the one between the U.S.S.R. and a group of nine Socialist countries where the resolution limit is specified as 50m.Available information even though not very clear seems to indicate that this resolution limit could be between 20 and 50m.There is also a proposal to use satellites for monitoring arms control and for crisis management by creating an International Satellite Monitoring Agency (ISMA). The huge expense that this would entail would be acceptable only ifISMA can monitor the superpowers and the arms race between them.

ISSN:0143-1161    

DOI:10.1080/01431168608954658

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Education and training in satellite remote sensing is constantly receiving increasing attention. Many educational and training facilities prevail. There exist nowadays international or regional or national facilities. In addition, some national facilities have an essential international function or have an additional regional function. Some of these facilities provide education and training on a permanent continuous basis, while others function on an occasional basis. The various facilities have different specializations and are oriented for specific strata of people.

ISSN:0143-1161    

DOI:10.1080/01431168608954659

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Light reflected from the Earth's surfacecan be describedin terms of its intensity and polarization and yet remote sensing has concerned itself with the measurement of intensity and has paid little attention to the measurement of polarization. In this review, imaging and non-imaging systems for measuring the state of polarization of reflected light are described, together with their associated problems. Field and laboratory measurements of the polarizingeffects of minerals, soils, vegetation, water and oil slicks are presented. It is recommended that future research could concentrate upon, first, establishing the precise relationships between polarization and surface factors such as moisture content, roughness, particle size and albedo and, secondly, the methods by whichpolarization imagery could be collected, processedand displayed.

ISSN:0143-1161    

DOI:10.1080/01431168608954660

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

LANDSAT imagery has been corrected for Earth curvature and rotation, satellite attitude errors and sensor non-linearities, it still contains significant geometric distortions with the centre of the scene only located to an accuracy of a few kilometres. For some applications these errors are unimportant but an increasing number of users need geometrically transformed imagery either for direct comparison with maps or for multitemporal analysis. To determine the transformation the user must select a number of ground control points, i.e. features which are readily identifiable on both the image and a map. The transformation matrix between image and map co-ordinates is then determined and the scene resampled using interpolation techniques.

ISSN:0143-1161    

DOI:10.1080/01431168608954661

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The tree classifier has proved to be an effective method of statistical pattern classification, but the designing of the tree structure is not usually easy. In this paper, a new design approach based on hierarchical clustering is proposed. The design principle and the algorithm of the method, as well as the experimental results for both test data and remote-sensing data, are discussed. The design process of the method is simple and the performance of the classifier designed by the method has been proved to be satisfactory.

ISSN:0143-1161    

DOI:10.1080/01431168608954662

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The tree classifier is an effective method in statistical pattern classification. In this paper, a new tree-classifier design approach based on a splitting algorithm is proposed. This method not only has the common advantages of the tree classifier, but also enables its user to make a trade-off between accuracy and economy of computing time, and to achieve satisfactory results with a relatively short computing time. Experimental classification for test data and remote-sensing data is discussed.

ISSN:0143-1161    

DOI:10.1080/01431168608954663

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Calculations of diffusely reflected radiance emerging at the top of the atmosphere for a known aerosol size distribution have been made using the radiative transfer equation. The computed radiance was compared with the CZCS radiance collected within 1-2 hours after the aerosol measurements from the same area. An optical depth of the Earth's atmosphere is inferred from the comparison. The procedure was carried out for wavelengths corresponding to the CZCS channels (443, 520, 550, 670 and 750nm). Values of optical depth are plotted against the wavelengthsto provide an optical depth spectrum. The results indicate that there isa strong dependenceof optical depth on the wavelength. Thus, the ratio of optical depths at different wavelengths throughout the whole spectrum is not constant. Also, at various aerosol concentrations of large particles, the ratio is found to be variable. This suggests that a precise value of the optical depth ratio cannot be easily estimated although the use of the ratio in an atmospheric correction algorithm can provide satisfactory accuracy. The computed radiance is found to be linearly related to the optical depth and, therefore, a simple approximation for the aerosol radiance based on a lineardependenceon the aerosol optical depth should be accurate. The study also shows that the effect due to misclassification between the contaminated and uncontaminated pixels by thin haze or cloud, is to cause a significant reduction in the optical depth ratio.(443)/.(550). The resultingvaluesof the optical depth ratio cannot beestimated by the approximation suggestedin Gordon and Clark (1981)and Gordon et al. (1983).

ISSN:0143-1161    

DOI:10.1080/01431168608954664

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Side-scan sonar data collected in 1977 and 1983 from the Bristol Channel are compared with 1978 SEASAT images, in order to determine the limiting physical dimensions of positive and negative topographic features detectable by SEASAT. The identification of sea-bed topography is related to a change in current speed which, in turn, is controlled bythe relief:water-depth ratio. In a water depth of 45mwith a surface current speed of about 70cms−1, for example, features > 11 m in relief and with a spacing > 500 m are visible.

ISSN:0143-1161    

DOI:10.1080/01431168608954665

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Airborne lidar measurements were performed over a deployed mono-molecular oleyl alcohol surface film (‘slick’), the physicochemical characteristics of which are known to be similar to biogenic organic compounds secreted by plankton and fish, and adjacent ‘clean’ sea surfaces in the North Sea. In the presence of the slick,the suppression of the Raman backscatter at 381 nmand of two spectral bands indicative of water column fluorescent organic material at 414 and 482 nm were observed. This effect is explained by two possible mechanisms giving rise to a modification of the transmission or coupling of the laser beam into the water column: (i) the damping of capillary and short gravity water waves by the oleyl alcohol slick, and (ii) the modification of the uppermost water layer by the oleyl alcohol film. The results obtained in the presenceof a slick are compared with data measured over a Murban crude-oil spill with the same lidar system off the coast of the U.S.A. The consequences of the lidar-monomolecular film experiments with regard to the remote detection of crude-oil spills and oil-thickness measurements with an airborne laser fluorosensing system will be discussed.

ISSN:0143-1161    

DOI:10.1080/01431168608954666

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor