ISSN:0143-1161    

DOI:10.1080/01431169408954127

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Analyses of remote-sensing imagery from a fractal perspective have become more frequent in the literature. However, one aspect which has not been considered specifically is how images integrate a mix of several, possibly very different, fractal processes. In this exploratory investigation, the fractal dimensions of sunlit and shadowed areas of surfaces of known fractal dimensions were determined. It was found that the shadowed areas lend to have fractal dimensions approaching 2.0, whereas, surprisingly, sunlit areas have fractal dimensions which are inversely related to the fractal dimension of the surface.

ISSN:0143-1161    

DOI:10.1080/01431169408954128

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this study, Earth location errors in AVHRR satellite data and methods for their correction are examined with particular application to oceanic regions far removed from ground control. A general correction procedure, using landmarks or Ground Control Points (GCPs) and taking into account landmark uncertainties, is presented. Correction functions arc derived as expansions for any complete basis. Operationally-available estimates of Earth location are used as a first-guess in developing the correction procedure. In particular, polynomial expansions are used to represent the correction functions which provide the basis for renavigating the satellite data. The coefficients of the polynomial expansions are obtained using the method of least-squares. The stability of the correction procedure with respect to. local errors in navigation, (i.e. within a scene) and how to select the correct order of the correction polynomials are examined. Uncertainty in extrapolating navigation corrections over remote regions is examined and quantified. The importance of landmark uncertainty in degrading renaviga-tion accuracy is also addressed. Several parameters are introduced to optimize the choice of GCPs and their distributions. The procedures which are developed are then applied to simulated and actual AVHRR imagery. Finally, the impact of local errors in navigation, which most likely arise from rapid variations in spacecraft attitude, on renavigation accuracy is emphasized and one possible solution proposed.

ISSN:0143-1161    

DOI:10.1080/01431169408954129

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The application of image processing algorithms, originally developed for satellite image analysis, has been shown to improve pattern recognition of environmental change and vegetation stress with medium-scale aerial photography. Image enhancement helps to identify subtle features and spatial patterns embedded in a digitized air photo transparency that might otherwise escape visual identification. Our procedure combines visual interpretation with computer-aided image enhancement, including Normalized Difference Vegetation Index (NDVI) and supervised and unsupervised classification. The motiviation for the application of these techniques came from the need to provide a multi-season record of environmental changes in the immediate vicinity of power generation facilities. The procedure involves simple, on-call, acquisition of colour infrared and colour aerial photography that can be electronically enhanced and evaluated, resulting in accurate, timely, and cost-efficient information on vegetation changes related to land management, weather, diseases, insects, or other environmental stressors.

ISSN:0143-1161    

DOI:10.1080/01431169408954130

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two segmentation and two unsupervised classification schemes are applied to four Landsat TM Antarctic scenes. The methods include the region-growing and the region-oriented segmentation approaches and the Divide-and-Conquer and the Mahalanobis classifiers. Combinations of spectral signatures and Grey Level Difference Vector (GLDV) textural measures are computed for each of the seven TM bands. Correlation matrices then are constructed to reduce the feature vector. Means, standard deviations, and angular second moments are selected, usually for TM channels 4, 5, and 6.

ISSN:0143-1161    

DOI:10.1080/01431169408954131

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Conventional classification techniques, both supervised and non-supervised, are used for the classification of remote sensing data on the basis of spectral signatures of the classes of interest, and, contextual techniques use both spectral and spatial information to improve the classification accuracies.

ISSN:0143-1161    

DOI:10.1080/01431169408954132

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

One of the biggest problems in automatic processing of synthetic aperture radar (SAR) imagery is the large amount of noise due to speckle. Some form of smoothing is needed before interpretation can take place. Traditionally, the amount of smoothing has been chosen in an arbitrary manner. Optimal smoothing filters, such as the Wiener filter, may be derived, but their implementation is a demanding task in most image handling systems. This paper suggests that by constraining image autocorrelations and smoothing filter weights to be functions with few parameters, a useful saving in the complexity of algorithms may be achieved, with little loss of filter performance. It is also shown that the performance of this approach is robust to the form of the autocorrelation function.

ISSN:0143-1161    

DOI:10.1080/01431169408954133

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Les images radar présentent une texture particulière, et essentiellement granulométrique qui nécessite des traitements spécifiques appropriés en vuc d'améliorer l'interpretation thématique. Cet article a pour objet la presentation d'une méthodologie originale, relative à des différenciations de tissus urbains, d'après une scène radar VARAN sur la région de la ville de Luc (VAR). Les méthodes de morphologie mathématique permettent de préparer ['image radar pour l'analyse texturale. L'outils statistique du variogramme est ensuite utilisé pour lever les confusions entre la granulométrie fine inhérente au speckle et la granulométrie urbaine.

ISSN:0143-1161    

DOI:10.1080/01431169408954134

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431169408954135

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431169408954136

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor