ISSN:0143-1161    

DOI:10.1080/01431168408948804

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0143-1161    

DOI:10.1080/01431168408948805

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The problem of radioacoustic sounding of the atmosphere is considered with diffraction effects taken into account for the bistatic scheme of sounding. Formulae are obtained for the power and frequency of the scattered signal. The influence of wind displacement, sound extinction and the finite dimensions of wave packets upon the scattered signal frequency is proved to be significant and should be taken into account mainly for the calculation of power characteristics

ISSN:0143-1161    

DOI:10.1080/01431168408948806

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The directional reflectance factor distribution spanning the entire exitance hemisphere was measured for a cotton row crop ( 39 per cent ground cover) as a function of the solar azimuth and zenith angles. Two spectral bands NOAA 7 AVHRR bands 1 ( 0.57-0.69 μ ) and 2 (0.71-0.99 μ ) were measured. Ancillary data consisted of leaf orientation distribution measurements, structural and agronomic measurements, as well as optical measurements of leaves and soil. Polar co-ordinate system plots of directional reflectance factor distributions and three-dimensional computer graphic plots of scattered flux were created from the radiometric data. These plots were used to study the dynamics of the directional reflectance factor distribution as a function of spectral band, geometric structure of the scene, solar zenith and azimuth angles and optical properties of the leaves and soil

ISSN:0143-1161    

DOI:10.1080/01431168408948807

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The use of high-resolution spectra (⩾ I nm resolution) obtained from plants with a ground-based spectroradiometer for selecting multiband scanners and determining bandwidth suitability is presented (350-1850 nm) The highly structured features of crop radiance requires careful analyses to minimize the number of bands, the irrelevent radiance data and subsequent digital analyses. Several structural features were clearly defined at early stages of plant development and became progressively indiscernible as maturity approached. These occurred at wavelengths known to be affected by chlorophyll concentration and leaf structure (e.g. 640-680 nm, and near infrared from 730-690 nm) by H and Mg compounds (480-520 nm bands) and water (720 nm) Several others varied without known association. Others varied little with crop development but coincided with the molecular absorption bands of different chemical elements (e.g. Ca and Fe, 430 nm and 02The bandwidths of the various structural features were compared to the bandwidths of the channels for several space- and airborne multispectral systems. The comparisons of the radiance values showed that only a few of the channels in each system had bandwidths corresponding to structural features associated with specific plant characteristics and chemical compounds. Thus, much of the spectral data obtained would have little specificity for identifying or measuring biophysical properties of crops. Similar care in the selection of filters for photographic systems would also be applicable. A numerical system for identifying bands of uniform radiance is presented to facilitate referencing of the various bands

ISSN:0143-1161    

DOI:10.1080/01431168408948808

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The objective of this study was the classification of a Mediterranean humid mesothermal area (Csa) of central Macedonia into land systems, using LANDSAT images (1:250000 in scale). The information obtained was combined with field survey work in order to study the wide range of natural environmental conditions of the area.

ISSN:0143-1161    

DOI:10.1080/01431168408948809

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Feature extraction is an important factor in determining the accuracy that can be attained in the classification of multispectral images. The traditional per point classification methods do not use all the available information, since they disregard the spatial relationships that exist among pixels belonging to the same class. In this paper, methods are developed to extract additional image spatial features by means of linear and non-linear local filtering. Feature selection methods are also developed, since it is usually not possible to use all the generated features. The classification stage is performed in a supervised mode using the maximum likelihood criterion. A quantitative analysis of the performance of the spatial features show that an overall increase in precision of classification is achieved, although at the expense of increased rejection levels, particularly on the borders between different fields.

ISSN:0143-1161    

DOI:10.1080/01431168408948810

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The presence of positive serial correlation (autocorrelation) in remotely sensed data results in an underestimate of the variance-covariance matrix when calculated using contiguous pixels. This underestimate produces an inflation inFstatistics. For a set of Thematic Mapper Simulator data (TMS), used to test the ability to discriminate a known geobotanical anomaly from its background, the inflation inFstatistics related to serial correlation is between 7 and 70 times. This means that significance tests of means of the special bands initially appear to suggest that the anomalous site is very different in spectral reflectance and emitance from its background sites. However, this difference often disappears and is always dramatically reduced when compared to frequency distributions of test statistics produced by the comparison of simulated training sets possessing equal means, but which are composed of autocorrelated observations.

ISSN:0143-1161    

DOI:10.1080/01431168408948811

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The arrival of the new generation of satellite sensors with improved spatial and radiometric resolution (Thematic Mapper and SPOT) requires a re-evaluation of techniques for system performance analysis. Furthermore, the high performance of these systems will place greater demands on resampling algorithms for geometric processing of the imagery. Both of these topics are discussed. A formalism for incorporating random sample-scene phase in system analysis is presented and an improved bicubic resampling function is proposed and compared to standard resampling functions with tests on real imagery.

ISSN:0143-1161    

DOI:10.1080/01431168408948812

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Simple and successful methods have been presented for deriving chlorophyll a concentrations from optical reflectance spectra of seawater, using information from only a few wavelengths. The characteristic vector method allows all wavelengths in a set of (low resolution) spectra to be analysed for signatures characteristic of different, independently varying phenomena and can therefore be used to evaluate the information content of different spectral ranges for chlorophyll determinations.

ISSN:0143-1161    

DOI:10.1080/01431168408948813

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor