最新刊期
卷 ， 期 1 ， 2000
- 摘要：The Sealing Cavity method for determining the emissivity of the target object simplified the measuring and computing process. According to above mentioned method, in this paper, the influence on the accurately measuring result of the undulation of target object emittance and environment emittance have been analyzed. Also, we discuss the effect of wavebands between different infrared radiometers. Through lots of experiments, the optimum contrast temperature difference between hot environment and cool environment is given. Finally, three conclusions are drawn to guide the measurement of emissivity.关键词：Emissivity;effective emissivity;Sealing Cavity method
- 157
- |
- 249
- |
- 5
发布时间：2021-06-10 - 摘要：Thermal infrared remote sensing technology supplies an attractive way to measure landsuface temperature （LST） on a large scale simultaneously. NOAAAVHRR data is commonly used in the inversion study of LST. But the inversion is a challenge for the scientists because of the complexity of land surface. So far splitwindow algorithm is a major solution to retrieve landsurface temperature from thermal infrared remote sensing data. But because of the obstacle to obtain the insitu validation measurements simultaneously, including landsurface temperature and emissivity especially in pixel scale, it is confined to judge directly which one is more precious and more applicable.\;In this paper, using radiative transfer code LOWTRAN7 and six standard atmosphere models supplied by it, we analyzed, by simulation, the sensibility of the six common splitwindow algorithms to the atmospheric profile error, including atmospheric water vapor profile and temperature profile. The sensibility to spectral emissivity, including the average emissivity and the differential emissivity between AVHRR channels 4 and 5, is also analyzed. It turns out that, （1） algorithms of SOB and UVM have less sensibility to atmospheric profile, and have more satisfactory accuracy of better than 1.5K; （2） most algorithms are more sensible to the mean emissivity than to the emissivity difference. Sobrino （1991） algorithm has the least sensibility to emissivity. As a result, we obtained an indirect criterion priliminarily for the six splitwindow algorithms.
- 175
- |
- 406
- |
- 6
发布时间：2021-06-10 - 摘要：Based on the Vector Radiative Transfer Theory （VRT） and SAR technology characteristics, several submodels for rice are constructed such as leaf scattering model, leaf extinction models, trunk scattering model, trunk extinction model and water reflection model. Then an integrated model including all the main physical processes of rice firstorder scattering mechanisms is achieved. By simulations using the validated model, the backscattering coefficient of the rice canopy which can be deduced from the SAR data will be obtained. It will be helpful in theoretical and methodological guidance for using SAR data to make rice fields mapping, rice growth monitoring and rice production forecasting more effectively, more economically and more expediently. In this paper, all of the models are introduced in detail and systema tically. Based on the simulation results, the variations of the rice backscattering coefficient with the date, incidence angle, wave band and polarization change are discussed. At the end of this article, some valuable quantificational results and practical conclusions are summarized.关键词：VRT;Backscattering coefficient;rice;microwave remote sensing
- 126
- |
- 374
- |
- 2
发布时间：2021-06-10 - 摘要：s: Airborne laser image and mapping system （ALIMS） which integrates kinematic GPS positioning system, laser range finder, attitude measurement unit and optical mechanical scanner into a rigid platform can generate DEM （digital elevation model） and geo referenced image rapidly and efficiently. We regard ALIMS as a 3D remote sensing system, because it can directly obtain 3D position together with spectral information. Kinematic GPS is a key sensor that is able to give the precise 3D position of the platform. In this paper we present the kinematic GPS technology and data processing techniques. First, we analyses the GPS technical requirement which can suit for ALIMS. For example, why do we need high differential GPS positioning technique, how to synchronize GPS data with remote sensing data, and why collecting high rate GPS data is important. Then, we discuss the GPS data processing procedure, including differential GPS processing, solution of pulse’s position, datum transformation, coordinate project and eccentric correction. In several airborne experiments we have applied kinematic GPS positioning technology and corresponded data processing, and the result is satisfactory.关键词：D remote sensing;kinematic GPS;data processing
- 136
- |
- 277
- |
- 1
发布时间：2021-06-10 - 摘要：This paper presents two models for describing error of transition curve features based on error of points on the curve. The error nature of such a curve depends on variance covariance matrices of endpoints. The first error model is based on root mean square error in normal direction of the transition curve. The second model is based on error in the maximum direction of the curve. Theoretically, the error model of maximum direction is more rigorous for describing error of transition curve lines. The error model of normal direction is a simplified model of the previous one and is widely used in describing error of straight lines.关键词：error model;GIS;transition curve feature
- 162
- |
- 202
- |
- 1
发布时间：2021-06-10 - 摘要：A wide variety of algorithms have been proposed to construct triangulation. They fall into three broad categories: divide\|and\|conquer, incremental insertion and triangulation growth. The first two groups of the methods have been extensively applied to many disciplines because of their easiness in implementation. They are, however, constrained either by their computational inefficiency or by their stringent demand on computer memory. In this paper a hybridized method is proposed to take advantage of both algorithms’ strengths so that these limitations could be overcome. In a test of 2533 points, the computation efficiency of the hybridized method is much higher than that of incremental insertion method in all cases, and is also higher than that of divide\|and\|conquer method in most cases. The best efficiency is achieved when the data points are partitioned into one\|tenth of the original size.
- 140
- |
- 762
- |
- 24
发布时间：2021-06-10 - 摘要：Spatial resolution is an important index in image quality evaluation. Modulation Transfer Function （MTF） is usually used to estimate the spatial resolution fo an image. Because of the image noise and the dispersion character of the sample data, smoothness and interpolation are two necessary links. Thus, the algorithm of smoothness and interpolation will directly affects the result of evaluation. Two algorithms of smoothness and two algorithms of interpolation have been applied to the experiments of evaluating two typical imagery according to eight experiment schemes. The influence machnism of the algorithms on image spatial resolution evaluation has been achieved, and a better algorithm of smoothness and a better algorithm of interpolation have been selected.关键词：smoothness;interpolation;image spatial resolution
- 187
- |
- 231
- |
- 3
发布时间：2021-06-10 - 摘要：Algal chlorophyll measurement is usually used to assess trophic status of lakes. The development of hyperspectral imaging enable it possible to detect spectral features of algal chlorophyll with high spectral resolution and to map the spatial distribution of algae in large lakes with great precision. This study was conducted to establish correlation between hyperspectral reflectance and algal chlorophyll concentration. The problem is complicated by the numerous suspensions and dissolved organic matters in inland water because optical effects of these pollutant substances often overwhelm spectral features of algae. The area studied in this paper is the Lake Taihu in the Yantze river delta, which becomes enriched quickly in nutrients and supports excessive growths of blue alga in summer. Reflectance spectrum of water in the range of 350 to 1050nm was measured by a GER\|1500 radiometer with a bandwidth of 1.6nm. The water was also sampled simultaneously to determine algal chlorophyll concentration and other water quality parameters in the laboratory. The position of reflectance peak near 700nm and reflectance ratio of R 705nm / R 675nm were found to be significantly correlated with algal chlorophyll concentration. Chlorophyll algorithms based on these spectral features are presented.关键词：chlorophyll;hyperspectral;remote sensing
- 202
- |
- 1728
- |
- 115
发布时间：2021-06-10 - 摘要：In the paper, considering the vegetation parameters of remote sensing information and crop eco\|physiological characteristics, the crop yield estimation model was firstly set up based on the variables derived from NOAA\|AVHRR data and crop photosynthesis. Among them, photosynthetic active radiation （PAR）, CPAP （Crop Photosynthetic Assimilation Potential, which reflects crop photosynthetic time and area）, and photosynthetic rate were calculated from remote sensing information and meteorological data. In the typical research area of North China Plain, the developed model was applied to regional crop yield distributions, it shows that the model has better precision. Secondly, taking into account the impact of CO\-2 doubling to agroecosystem and its influences on winter wheat, the crop yield estimating model based on remote sensing data and plant photosynthesis was further developed, and the regional crop yield under CO\-2 doubling was estimated using the model. The further changes of crop yield distributions were given using the developed model.关键词：CO\-2 multiplication;crop yield response model of 2×CO\-2 by remote sensing and plant photosynthesis;winter wheat yield monitoring;North China Plain
- 157
- |
- 251
- |
- 1
发布时间：2021-06-10 - 摘要：The radar backscattering from the ocean surface results mainly from the Bragg scattering caused by the short gravity waves, which are related to wind vector, boundary layer phenomena, etc. Hence, it is reasonable to retrieve the wind field information from the radar cross section of the ocean surface. Much work has been done on deriving the ocean spectra from SAR imagery and wind speed from radar cross section. In this paper, the （SIR C）/（X SAR） data acquired in April, 1994 are analyzed over the South China Sea. Firstly, the SAR image spectra are calculated, and the wind direction is estimated. The wind speed is derived using the sigma naught of the C band data with the CMOD4 model. The results are validated with the composite model. It is shown that SAR is one of useful tools for the retrieval of comprehensive wind information over the ocean.关键词：SIR C/X SAR;wind vector;scattering model
- 149
- |
- 230
- |
- 7
发布时间：2021-06-10 - 摘要：Detection of the ship wake from SAR imagery is very significant. Most of the methods detecting ship wakes from SAR imagery are based on Radon transform appending condition test using prior knowledge. In the paper we introduce the patterns of three main kinds of ship wakes. Then we analyse four limitations of the method that applies Radon transform to detect ship wake in SAR ocean images. In order to improve the limitations we describe another method to detect Vshape ship wake. At first, we filter the SAR images to suppress the speckle noise, then, use Static Boundary Contour System based on biological vision to process the filtered images. Finally Radon transform is applied to enhance the ship wake. We describe two parts of the Static Boundary Contour System in the paper. The first part is Static Oriented Contrast which is used to determine the local good orient of the contrast difference in the input, and the second pasrt is CooperativeCompetitive Loop which is used to sharpen, group and select the edge. We test the algorithm by using ERS1 SAR coean images. The result deriving from the new algorithm is better than that from simple Radon transform.
- 169
- |
- 243
- |
- 9
发布时间：2021-06-10 - 摘要：Owing to the anisotropic and the biharmonic nature of microwave radar backscatter on spaceborne scatterometer, and to the scatter model function nolinear and the existence of various noise sources in the measurements in addition to the model function, the retrieval wind results consist of as many as four wind directions. We introduce a modified model approach to estimate the unique synoptic oceanic wind field from backscatter of spaceborne scatterometer. The comparison those estimated from numerical simulation with real data shows the agreement largely in wind direction and in the true wind speed. It is demonstrated very successfully that the simulated or real scatterometer data with the modified model estimation has been retrieved in this paper.关键词：wind direction ambiguity removal;modelbased estimation;scatterometer
- 154
- |
- 331
- |
- 7
发布时间：2021-06-10 - 摘要：At present, GIS has been widely applied to the study of wildlife habitat. However, GIS, which is a tool of spatial data analysis and processing, lacks of the capacity of heuristic reasoning. Therefore, it is an important way to solve this problem by the integration of Bayesian statistics inference with GIS. in this article, the Naban river nature reserve of Xishuangbanna was taken as an experimental area, GIS and multivariate statistical techniques were applied to the development of two logistic multiple regression models for Bos gaurus readei habitat: trend surface model and environmental model. Independent variables were locational coordinates in the first model, and a set of environmental factors in the second model. Bayesian statistics were then used to integrate the two models into a Bayesian integrated model. The results show that the Bayesian integrated model is superior to the environmental model and can be applied to wildlife habitat evaluation.关键词：GIS;bayesian statistics inference;habitat;Xishuangbanna
- 164
- |
- 493
- |
- 12
发布时间：2021-06-10 - 摘要：Lots of remote sensing images have been accumulated in the repository without being efficient used, on the other hand, many application projects called for the share of the remote sensing images. This problem can be resolved by the Web publishing of remote sensing images. In this paper, a systematic research on the web publishing of remote sensing image was conducted, according to the characters of Internet and remote sensing image. A publishing architecture and respective technical problems were given and solved, the remote sensing image publishing system was implemented according to it, the integration of it into the WebGIS was also discussed.\;The whole publishing procedure is implemented in 5 steps: 1, the user submits the request for the remote sensing image of a certain range in the web browser from the client side. 2, the request is sent to the server and the server queries the database to find the images which are covered in the range. 3, a new image is obtained by combining the images being covered. 4, a size suitable image is obtained by extracting from the new image. 5, the resultant image is sent back to the client and displayed to the user in the web browser. In this way, the user can have access to the remote sensing images by most cut down the net work trans portation.关键词：remote sensing image;WWW;WebGIS;Internet
- 236
- |
- 400
- |
- 11
发布时间：2021-06-10 - 摘要：The rapid development of Internet GIS makes it possible to access spatial information, however, the complex and various geodata formats limit users to transparently access remote geodata and seamlessly process differently historical, different data format in enduser side. The paper brings up the concept of virtual DBMS in server side for organization and management of distributed heterogeneous database and finishment of heterogeneous geodata access and interoperability. By VGDBMS, users can acess and process geoinformation being in different locations. Finally, as an aplication example of Internet GIS GeoSurf, based on Java, crossplatform, distributed computing and browser/server, is represented in support of above mentioned issues.关键词：Interoperability;Internet GIS;Distributed;Browser/Server;VGDBMS
- 139
- |
- 355
- |
- 6
发布时间：2021-06-10
- Postal code：100190
- Tel：010-58887052 Email：nrsb@aircas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备20021838号-9
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0