摘要:

This paper deals with the prediction and management of regional and environmental noise using remote sensing techniques. Landsat-MSS and -TM data are used to estimate noise pollution by means of a group method of data handling. They estimate ground roughness from the proportion of the area occupied by buildings thus determining the shielding factor of noise propagation on the ground. The noise level predicted by the method presented in this paper showed a satisfactory agreement with that obtained from measurements from various other cases in urban areas.

ISSN:0143-1161    

DOI:10.1080/01431169308904284

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The objective was to quantify and analyse the spectral, spatial and temporal variability of solar radiation reflected from arctic tundra vegetation at a study site in the Brooks Range foothills of northern Alaska. Spectral radiance data from hand-held radiometers and the SPOT HRV sensor were sampled along hillslope transects (toposequences) and within four vegetation community types. The spatial trend of normalised difference vegetation index (NDVI) along the toposequences corresponded to variations in the abundance of green vegetation matter and in vegetation composition. A marked temporal increase in the NDVI occurred along the toposequences from the beginning of the growing season (mid-June) to peak green up (end of July). The spectral signatures of three tundra dominant vegetation communities, dry heath, moist tussock and wet sedge, were moderately separable, with dry heath being most separable. The overall separability of the major community types was similar at all times during the growing season, with the most divergent signatures occurring in late July during maximum greenness. Some of the important ecological features of the arctic tundra landscape are not resolved by the SPOT HRV sensor in multi-spectral mode, in spite of its high (20 m) spatial resolution.

ISSN:0143-1161    

DOI:10.1080/01431169308904285

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An earlier analysis of the data acquired by TIMS (Thermal Infrared Multispectral Scanner) operating from the NASA C-130 during HAPEX (Hydro-logic Atmospheric Pilot Experiment) MOBILHY experiment, showed that the brightness temperatures for all six channels were too high, and that the magnitude of the error was more or less a function of the aircraft altitude. This problem is certainly due to the ambient air stream which could cool the two blackbodies used as reference targets. To correct the TIMS data, the PRT5 (Precision Thermometer) non-scanning radiometer is used. The PRT5/TIMS comparison is based upon a relationship between a combination of the TIMS surface brightness temperatures,Tt, and the PRT5 surface brightness temperature, T. TIMS and PRT5 corresponding transects are superposed by maximizing the linear correlation between the two sets of temperatures. The correlations are always greater than 0-92.TcandTk, the cold and hoi actual blackbody temperatures, can be deduced from the slope and the origin of the preceding fit. Final precision on TIMS temperature is about 1°C. The validation, made with the ground K.T17 radiothermometer, gives satisfactory results. A simple empirical correction is deduced from the 22 mid altitude corrected transects. It gives the same precision on the temperature retrieval when it is applied on high altitude TIMS measurements for which the PRT5 is not available. As expected, the correction is larger for high altitude flights—until 10° C and more—than Tor mid altitude flights—from 2 to 5° C.

ISSN:0143-1161    

DOI:10.1080/01431169308904286

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Satellite microwave brightness temperatures (TB'S) have been shown, in previous studies for semi-arid environments, to correlate well with the antecedent precipitation index (API), a soil moisture indicator. The current study, using the Special Sensor Microwave/Imager (SSM/I), continued this work for parts of the U.S. Corn and Wheat Belts, which included areas with a more humid climate, a denser natural vegetation cover, and a different mix of agricultural crop types. Four years (1987-1990) of SSM/I data at 19 and 37GHz, daily precipitation and temperature data from weather stations, andAPIcalculated from the weather data were processed, geo-referenced, and averaged to equation pending latitude-longitude grid quadrants. Correlation results betweenTBat 19 GHz and API were highly dependent on geographical location. Correlation coefficients (r values) ranged from —0-6 to —0-85 for the semi-arid parts of the study area and from —03 to —0-7 for the more humid and more densely vegetated parts. R values were also higher for the very dry and very wet years (—0-5 to —085) than for the 'normal’ year (—0-3 to —0-65). Similar to previous results, the Microwave Polarization Difference Index (MPDI), based on the 37 GHz data, was found to correspond to variations in vegetation cover. The MPDI was used to develop a linear regression model to estimateAPIfromTB. Correlation between estimated and calculatedAPIswas also geographically and time dependent. Comparison ofAPIwith some field soil moisture measurements showed a similar trend, which provided some degree of confidence in usingAPIas an indicator of soil moisture.

ISSN:0143-1161    

DOI:10.1080/01431169308904287

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The amount of linearly polarized light reflected by a wheat canopy was measured using a polarizing filter attached to a radiometer at two wavelengths (478 nm and 668 nm) and three view zenith angles (60°, 70°, 80°). Measurements were carried out in the anti-solar direction in the principal plane, with relative azimuth between Sun and view directions being 180°. It is found that the degree of polarization (DOP) and mean polarized radiance (R¯Q) between stages is statistically significant at view zenith angles of 70° and 80°, in the blue wavelength region. It is concluded thatDOPand R¯Qare better indicators of the onset of heading stage. Calculations of polarized reflectance using Fresnel reflection equations are also presented.

ISSN:0143-1161    

DOI:10.1080/01431169308904288

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This study describes procedures for analysis of data from Landsat MSS and Indian Remote Sensing Satellite IRS-IA for pre-harvest wheat yield prediction. A linear yield-spectral index model has been developed wherein radiance values have been used instead of digital counts in order to take care of data from different satellites/sensors. The spectral ratios have been normalized using a crop growth profile so that alt the values correspond to maximum vegetative growth. Using these procedures district-wise grain yield prediction of wheat for the Haryana state in India for the 1988-89 growing season was carried out. Yield estimates from Landsat MSS and IRS-IA LISS-1 data were in good agreement with one another. The maximum deviation of estimated yield by IRS-IA data from that of Bureau of Economics and Statistics (BES) of the government was 18 per cent,

ISSN:0143-1161    

DOI:10.1080/01431169308904289

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Recent research has shown that general trends in forest leaf area index along regional climatic gradients can be adequately characterized by using ratios of near-infrared and red reflectances. However it has proven difficult to represent properly the spatial distribution of Leaf Area Index (LAI) at sub-regional scales such as small catchments. The key problem at Thematic Mapper scale is the variation in canopy closure and understorey contribution, which dramatically influences near-infrared reflectance from conifer forests, [n this paper, a new spectral index is presented to estimate LAI of conifer forests using a combination of Red, NIR and mid-IR reflectances from the Landsat Thematic Mapper (TM). A simulation system (RHESSys) was used first, to generate potential vegetation patterns around a watershed in order to test them against remotely-sensed vegetation patterns, and secondly, to test the sensitivity of forest ecosystem processes to LAT estimated from combinations of the Thematic Mapper data

ISSN:0143-1161    

DOI:10.1080/01431169308904290

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Landsat-MSS data were used to estimate pasture biomass, cover and greenness of semi-arid grassland in central western New South Wales, Australia. The green pasture dominated the reflectance and while green cover, green biomass and percentage green were estimated to acceptable levels (±9-7 per cent, ± 0-35t ha-1 and ±M11 6 per cent respectively); it was not possible to estimate total pasture or brown pasture variables. Variability within relatively homogenous pastures is so large that the regression models between reflectance and pasture variables were not significantly different for the three pasture types analysed. Information on green biomass, cover and curing are useful for monitoring changes in pasture condition and in bushfire prediction models.

ISSN:0143-1161    

DOI:10.1080/01431169308904291

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In digital image processing for remote sensing there is often a need to interpolate an image. Examples occur in scale magnification, image registration, geometric correction, etc. On the other hand, this image can be subject to several sources of degradation and it would be interesting to compensate also for this degradation in the interpolation process. Therefore, this article addresses the problem of combining interpolation and restoration in a single operation, thereby reducing the computational effort. This is done by means of two-dimensional, separable, Finite Impulse Response (FIR) filters. The ideal low pass FIR filter for interpolation is modified to account for the restoration process. The Modified Inverse Filter (M1F) and the Wiener Filter (WF) are used for this purpose. The proposed methods are applied to the interpolation-restoration of Landsat-5 Thematic Mapper data. The later process takes into account the degradation due to optics, detector and electronic filtering. A comparison with the Parametric Cubic Convolution (PCC) technique is made. The experimental results consist of interpolation-restoration processes of Landsat-5 Thematic Mapper images from 30 m to 15 m (scale magnification) but they could also be generalized to include deblurring on more general interpolation problems, like geometric correction

ISSN:0143-1161    

DOI:10.1080/01431169308904292

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This study focused on investigating the possibility of combining the piecewise linear classifier (PLC) with simple spatial post-processing to improve the classification accuracies of spectrally classified images. The PLC was employed to classify video images. Spatial post-processing was then applied to the classified images. This technique was found to enhance classification accuracies considerably with only a moderate increase in processing time. Since spatially processed classification results were scene-dependent, it was important to choose an appropriate size of spatial filter for a study area. However, trade-offs between classification accuracy and processing speed with increasing size of spatial filter could be determined by trial and error.

ISSN:0143-1161    

DOI:10.1080/01431169308904293

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor