最新刊期
卷 ， 期 1 ， 2004
- 摘要：Fuzziness of spatial data is one of the difficult issues of current GIS research fields, However, existing GIS data model basically does not have the ability of describing, processing and analyzing the fuzziness of spatial data, which is very easy to make information loss in data processing. Fuzzy objects are defined to describe fuzziness of geographical phenomena and processes. Every element of an object does not always belong to one object, but can belong to several fuzzy objects with a fuzzy number indicating degree it belongs to the object. In this article, we combine the advantages of rough set with that of fuzzy set to express fuzzy objects. First, giving arbitrary two real numbers α, β and letting 0< β≤α ≤1,then, a fuzzy object A can be described as combination of down approximation RA α and upper approximation RA β using rough set. Second the interior of A can be defined as RA α , its boundary as RA β-RA α , and its exterior as U RA β, U is the domain. Finally, the 9 interxection model of spatial topological relations proposed by Egenhofer can be extended by using the new definition of object’s interior, boundary and exterior, and the topological relations between two fuzzy regions, and between a fuzzy region and a fuzzy line under the extended model are researched. There are three types of region/region topological relations, such as fuzzy regions and fuzzy regions （FF）, fuzzy regions and crisp regions（FC）and crisp regions and crisp regions（CC）, and four types of line regions topological relations, such as fuzzy regions and fuzzy lines（FF）, fuzzy regions and crisp lines（FC）, crisp regions and fuzzy lines（CF）and crisp regions and crisp lines（CC）in the paper. In contrast to 9 intersection model, the number of region/region topological relations discerned by extended model is 26 and that of line/region is 38, which is much more than that of 9 intersection model can be discerned. Generally, unlike the 9 intersection, the extended model has following advantages a fuzzy:1) it is enabled to describe the fuzzy objects and crisp objects in a union framework, 2)the conventional method of spatial relation describing topological relations is a special instance of it, 3) it studies the topological relations of fuzzy objects in details, and 4) it makes spatial data model enable to model the sptial phenomena with fuzziness and enhances the ability and precision of spatial data modeling.关键词：Fuzzy objects;fuzzy set;rough set;topological relations
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发布时间：2021-06-10 - 摘要：Spatial data is one of the fundamental parts of GIS.Uncertainty of spatial data can directly affect the quality of digital products and reliability of GIS based decision making and is regarded as one of the fundamental theoretical research issues.In recent years,positional uncertainty of line segments is a research focus.Several models have been presented by other scholars,for example ε band, e band, g band,and H band.Among these existing models, the ε band has been widely used due to its advantage of fixed band width.But it is difficult to determine the band width,which limits its further application.In this paper,we expand the model of H band in literature and present an uncertainty band of average entropy based on average information entropy of the whole line segment.The new model absorbs the strongpoint of ε band and at the same time takes the asymmetry of error distribution in line segment into consideration.It is a comparatively suitable measurement index of the positional uncertainty of line segments.关键词：line segment;positional uncertainty;ε band;average information entropy;band of average entropy
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发布时间：2021-06-10 - 摘要：This paper firstly introduces basic methods for identifying and tracking MCS ,and points out their advantages and disadventages. It then improves the algorithm of area overlapped method. Secondly, from the shape characters and essence attributes（e.g.textural attributes）of flow shaped group moving targets, the paper brings forward several kinds of method for constructing matching template. By considering the whole description, geometric shape and immovability moments characteristic of flow shaped group moving targets and its essence attributer, the templates matching is performed by using the principle of choosing minimum Eucliddistance, Meanwhile, the method of identifying and tracking targets is realized by using the arithmetic of matching across and updating elements of the matching templates in turn. The experiments show that the methods and skills can make a computer to automatically identify and track these multi flow shaped moving targets such as MCS . It is full of availability to identify and track th MCS by using them.
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发布时间：2021-06-10 - 摘要：MODIS method is a sensor to get the data by multi detector observation, among that 1km resolution waveband needs 10 detectors to scan at the same time, 500m resolution waveband needs 20 detectors, and 250m resolution waveband needs 40 detectors. The adoption of this technology has improved the scanning and data collection efficiency. However, there is a problem of the consistency between so many detectors, especially after the satellite is launched into the space the unexpected electromagnetism environment, it is very difficult to make so many detectors completely consistent. Therefore, the response discrepancy between the detectors will cause certain stripe in MODIS sensor, and the most serious stripe is in MODIS waveband 33-36. Some detectors of waveband 36 and 35 cannot reach the original defined NE Δ T . More stripe appears in the 6th, 7th and 8th detectors of waveband 34, and the 1st detector of waveband 33. Stripe also exists in other infrared waveband and visible waveband; there the stripe of window waveband is usually lower, while the stripe of atmospheric detecting waveband is more serious. This kind of stripe will cause much serious influence to the retrieving precision of MODIS quantitative products. In order to reduce the influence of MODIS stripe and improve the retrieving precision of remote sensing quantified products as soon as possible, we developed a wavelet analysis method to de stripe MODIS data. With this method, we remove the stripe of some different wave bands. These are waveband 36, 35, 34 and 33 detecting the phsical character of the cloud top, waveband 30 detecting the ozone, waveband 29, 28 and 27 detecting the water vapor, and the waveband 25, 24 and 23 detecting the atmospheric temperature. We describe a wavelet method for recovery of MODIS data from its stripe signals. Our work is organized into four broad sections. Section 1 will introduce wavelet shrinkage method for de noising noisy data; compare the character of the wavelet method and the FFT method in de noising processing. The objective of section 2 to find out the scale of MODIS stripe by the wavelet analysis for MODIS stripe data using continues wavelet transforms. Section 3 analyses stripe noise data pattern for the MODIS level 1B stripe data, present the wavelet shrinkage method for MODIS level 1B data. Section 4 will provide a comparson for MODIS cloud product and atmospheric profile product between the original data and de striped data. We can find that there is an improvement in MODIS cloud product and atmopheric profile product after de striping. And we can get more understanding for the stripe regular pattern.关键词：MODIS striping;Wavelet;De striping
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发布时间：2021-06-10 - 摘要：The optimization approach is one of the most promising methods for retrieval of water constituents in case 2 waters,but almost previous applications of this approach suffer from their local search techniques. In this study, a genetic algorithm is developed as a global optimization scheme to simultaneously retrieve concentrations of chlorophyll, suspended sediment and yellow substance. To separate the contributions to the radiance spectra by co exiting constituents, two reflectance ratios were embodied to the objective function,and a real valued genetic algorithm was used to optimize it. The performance of the algorithm is demonstrated with a simulated data set. Under noise free conditions, three water constituents are estimated accurately. Tests with noisy data show that the algorithm is robust against errors in the reflectance data.关键词：case 2 waters;ocean color remote sensing;inversion;genetic algorithm
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发布时间：2021-06-10 - 摘要：One of basis of water color remote sensing is to obtain and analyze the optical properties of the waterbodies. The optical properties of waters includes two aspects, Apparent Optical Properties（AOPs） and Inherent Optical Properties（IOPs）. Generally speaking, there are two relatively independent and complementary methods of in situ AOPs measurements, the profiling method and above water method. This paper focus on an above water method for the measurements of the AOPs which are directly related to the water color sensing parameters. In order to meet ocean color sensing requirements, the in situ measurements have to be able to derive:water leaving radiance L w , the normalized L wN , remote sensing reflectance R rs , irradiance reflectance just beneath water surface R （0 -）, etc. NASA ocean optic protocols deal mainly with CASE Ⅰ waters, while the most waterbodies of our coastal zone and lakes are CASE Ⅱ ones. The CASE Ⅱ water related measurement parameterization will be discussed. Some new methods are given for deriving the critical parameters in processing and analysing the data from above water method.关键词：ocean color sensing;water spectral;spectral measurement methods
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发布时间：2021-06-10 - 摘要：In this paper, a scale space clustering algorithm based on mathematical morphology operators（MSCMO） is proposed. The data are firstly converted into a binary image, the noises are then deleted with close open operators. A scale space is constructed with the close operator and structure elements as well as increased size. The connected cells merge with each other with the increasing scale until all of them combine into one. We suggest this is just a multi scale hierarchy clustering process considering the data under the connected cells into one class. One of the biggest advantages is that we do not need to set the cluster number before hand, it is fixed in the end on the cluster number which spans the longest scale range （with the longest`scale survival time’）. Besides, less arguments the ability to extract clusters with arbitrary shapes, and the robustness against noises are also the advantages of MSCMO. The validity and practicality of the algorithm are validated with constructed data and earthquake data.关键词：mathematical morphology;scale space;clustering
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发布时间：2021-06-10 - 摘要：Because of disturbance from inside or outside of sensors,there is much noise in the remote sensing image.People always filtrate image in order to improve its quality.Traditional filters are based on image’s space dimension.As a result,they usually blur the edges while smooth the image;or make image rough while enhance image’s edges contrarily. The adaptive filter in this articls,AFS（Adaptive Filter based on Spectrum）,uses the spectral information of multispectral or hyperspectral remote sensing images to smooth the even object,strengthen edges and keep the spectra of exceptional point,line orparcel of image. The key of AFS is how to complete the choosimg pixels in one filter mask based on pixels’spectral information. This method is also a kind of convolution operation to images,the difference between AFS and traditional smooth method is operating with pixels in filter mask selectively.We give some weight to valid pixels and give zero weight to invalid pixels in the filter mask,then use this filter to operate with image.关键词：remote sensing image;smooth;adaptive filter
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发布时间：2021-06-10 - 摘要：Due to some uncertain reasons, many seaWiFS satellite images are corrupted by impulse noise. In this paper, we firstly analyzed the characteristics of impulse noise and proposed a new rank ordered filter based on the difference of sequence of mean and standard deviation ratio, which is named as Statistical Ratio Rank Ordered Differences Filter （SRROD filter）. Second, We described the impulse noise detection and removal algorithm in detail. Similar to traditional median filter, the processing of SRROD filter is implemented by a moving window concerning to different size of neighborhood. Compared with median filter and other existing filters, our filter could effectively remove impulse noises while preserving other valid pixels without or only with little modification, with the cost of about 10 times extra computing time than median filter. To better assess the noise removal quality, we have derived a more reasonable variable to estimate the image quality. That was the Effective Peak Signal to Noise Ratio（ EPSNR ）, instead of the traditional Peak Signal to Noise Ratio （PSNR） . The estimation of EPSNR also showed that much better improvement has been achieved with our algorithm than median filter. In our algorithm, through controlling the value of lower and upper threshold, different filter effect could be achieved. One of the key to successfully remove impulse noise is the way to choose an optimal threshold pair. Thus we also made fully discussion of finding an optimal threshold pair. Based on the estimation and assessment for the distribution map of the EPSNR according to different lower and upper threshold pairs, a nearly optimal threshold could be found. The Laplacian transformation was found very useful in finding this optimal threshold pair. The estimated optimal threshold pair was applyied to a full scene SeaWiFS image（Channel 2）and obtained a fairly good result, in which the result was also shown in our paper. Finally, some concluding remarks and limitations of our algorithm as well as the suggestions are given. The further work to be conducted also presented in the conclusion section.关键词：impulse noise;SRROD filter;SeaWiFS imagery
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发布时间：2021-06-10 - 摘要：Spatially Modulation Imaging Fourier Transform Spectrometer（SMIFTS） is an important space remote sensor for research and application. In this paper, a prototype of IFTS based on Sagnac interferometer is introduced. The field Fourier Transform spectral imaging experiment is carried out with the prototype and Fourier Transform image in visible and near infrared（VNIR） region is obtained. By processing and Fourier Transforming interferogram of each pixel, spectral image and pixel spectra is extracted with distinct spctral character.关键词：remote sensing;VNIR;prototype of Sagnac type IFTS;field Fourier Transform spectral imaging experiment
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发布时间：2021-06-10 - 摘要：Monitoring urban vegetation is one of the major environmental applications in remote sensing today.As the main data sources for urban vegetation high resolution imagery provides a good basis for recognizing and monitoring small scale structure changes. Going far beyond the methodical limits of pixel based and manual interpretation approaches,multi resolution image segmentation and object oriented image analysis approaches are used for extracting information from airborne remote sensing data.This paper presents a snapshot of work to detect vegetation information in Daqing city using this new patented technique. It allows the segmentation of an image into highly homogeneous image objects in any chosen resolution and the generation of a network of image objects. The process does not classify single pixel but rather image object.Not only spectral information but also spatial, physical and contextual characteristics of image objects are used for classification.Classification is conducted by fuzzy logic,and image objects are evaluated using membership function classifiers.Membership functions are used to produce class description, which consists of a set of fuzzy expressions from appropriate sample objects.The result of vegetation information extraction is promising and the precision of classification is higher than other conventional processes.It is obvious that this new image analysis approach offers a satisfying solution to extract information quickly and efficiently.关键词：remote sensing;multi resolution segmentation;object oriented;urban vegetation
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发布时间：2021-06-10 - 摘要：Roughness of soil surface performs a remarkable inference to bi directional reflectance function of ground,and it is a variable.So it’s one of the important factor that affect the precision of the remote sensing for soil water content.Though analyzing the physical course of soil surface reflecting under the inference of soil water,this paper demonstrated that the relationship between soil reflected spectrum and the soil water content obeys the Beer Law,and that the essential cause of soil sruface roughness affecting the soil reflectance is the slant of sub slops on clod surface which result in the increasing of the raer of multi reflecting light.Basing on it,a remote sensing mode for soil water remote sensing on rough surface is proposde in this paper.The result of experimental data showed that the model has a satisfied precision.关键词：soil water content;roughness;BRDF;remote sensing model
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发布时间：2021-06-10 - 摘要：This study is based on the rank difference of the nitrogenous nutrition level by the man made style through two years rice farm experiment about the difference of the nitrogenous nitrition level. Using linear and non linear and stepwise multiple regression methods, the estimation models about LAI of rice have been built on the basis of the experimental data in 1999 which where evaluatde and validated with experimental data of the year 2000 as training samples. The results show that there are the ralationships between the characteristic variables of hyperspectra and LAI . From the results of precision analysis, the models that the vegetation indices variables of sum of the 1st derivative value within red edge （ SDr） and the blue edge （ SDb） are the best one of estimating LAI of Rice by hyperspectral remote sensing data.关键词：rice;LAI;hyperspectral remote sensing;estimate models
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发布时间：2021-06-10 - 摘要：Digital Earth will be a multi resolution, four dimensional virtual representation of our planet that enables a person to explore and interact with the vast amounts of natural and cultural information gathered about the Earth. It needs Interactive 3 D visualisation, display and navigation through immersed and non immersed environments; it also needs high performance computation to create derived information and model simulations on demand, storage and real time access to very large, multi resolution datasets, fusion of satellite imagery and other geo referenced data sources of diverse content, satellite and terrestrial broadband networks for high data rate transmission, interaction, and collaboration, standards and metadata for interoperability among and access to differing geo spatial databases are inevitable. Digital Earth concept becomes an international cooperative program instead of merely one country’s initiative. So far, Grid technique is the best solution for Digital Earth. Digiatl Earth can only be done through the interaction of people, heterogeneous computing resources, information systems, and instruments, all of which are geographically and organizationally dispersed. Earth observation includes information acquisition, processing and applications. Information acquisition provides a vast amount of spatial adta for building the fabric resource infrastructure. Information processing means that spatial information processing middleware is used with distributed large, secure grid computing resources for real time processing of all kinds of spatial data. With the help of GIS, we are currently working on the development of core middleware for Earth observation data processing and applications. The results will be available soon.关键词：Digital Earth;grid;virtual organization;spatial information grid;telegeoprocessing
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发布时间：2021-06-10
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