The methods for supervised and unsupervised classification of remote sensing images are reviewed in this paper. The main problems discussed include the merits, shortages and application fields and conditions of these methods. An integrated evaluation of these methods is also given. The future developing trends and the key points in the study of remote sensing image classification are dealt with at the end of this paper.
The Urban heat island (UHI) effect has been increasing so prominently that the measures for quantitative monitoring, analysis and evaluation of the UHI effect have become one of the most important fields in current urban climate and environment researches. This paper deals systematically with data sources, methods and results of applying remote sensing to the study of urban heat island, and gives a detailed review of researches on UHI conducted by experts all over the world in such aspects as its thermal pattern, process change regularity and causes. On such a basis, the paper predicts the development trend of applying remote sensing to studying urban heat island in future.
Smart city is the inevitable choice for the development of China’s new urbanization. As a product of informatization and urban integration, smart city is gradually realized as an efficient and fine tool for managing people, money, material and things intelligently. The study of influence of UAV remote sensing technology in the construction of intelligent city plays an important role in accelerating the construction of smart cities. In this paper, the authors first reviewed the definition and development status of smart city, and then introduced the applications of unmanned aerial vehicle (UAV) from urban planning, illegal construction supervision, engineering environmental management, waste management, intelligent transportation, and other aspects.Finally, the development tendency was discussed.
Algorithms for identifying convexity-concavity of a simple polygon has a very important application in many fields. The authors analyzed the present popular algorithms for identifying convexity-concavity of a simple polygon such as angling method, left-right-point method, vector-area method, vector-product method, raying method, slopping method and extremity-vertices-order method. A detailed derivation of these algorithms has revealed that these algorithms can all use the formula b=p*m as the expression, and are equivalent to each other in nature; nevertheless, the pole-order method still have some problems to be further studied. Based on an analysis of the computation, the authors hold that theoretically the vector-product method, the slopping method and the raying method could be used effectively in programming.
Texture plays a very important role in image retrieval and classification, and texture feature extraction has been a research hotspot. Most present existing texture extraction algorithms can be only used to calculate texture features of gray image. Texture extraction algorithm for color image is very few. Referring to the analytical method of gray level co-occurrence matrix (GLCM),the authors analyzed the influence law of parameters (direction,distance,grayscale,window size)on GLCM texture features of color image. A color image texture feature extraction method(color GLCM,CGLCM)based on GLCM was realized. Through analyzing the influence law of these parameters on four texture features(ASM(angular second moment),Entropy,Contrast,Correlation),a proper parameter value range was given and the CGLCM method was optimized. The results of comparing CGLCM method with GLCM method show that the four texture features calculated with CGLCM method have better robustness and identification capability. These results can provide reference for image retrieval and classification based on texture information.
Using computer image integration technique, the multiple geoscience information such as geological, remote sensing, hydtogeological, geophysical and geochemical informations are comprehensively processed The technique consists of the information input, registration, interpolation, and the enhancement, decomposition, abstraction, classification, overlay and combination process procedures. This technique has been tested on Shengyuan Basin. The Geological environment of the basin was studied by image enhancement and overlay technique. It is suggested that the basin was a volcanic centre of central eruption during the late jurassic and was superimposed by polygonal block-faulting during Cretaceous, forming a ring-block model of ore-field structure. The U, Th, K distribution pattern and its geological. significance have been analyzed using the decomposition and overlay technique of image information. It has been pointed out that the above pattern .is. controlled by the stratigraphic-structural factors, esp cially the high-content field of uranium, besides the NE and EW trending faults, the SN trending. fault-system is of great: importance in controlling the distribution of uranium in the region. On the basis of compositing and abstracting the prospecting criteria the target areas have been preliminarily selected. An information classification was used for the general evaluation of uranium resources in Shengyuan Basin With the help of the information procesing technique on computer some new insights about basic geological problem in this previously well-studied region have been obtained. Six promising areas have been selected and tested. Based on the research work mentioned above, a comprehensive technique system of multiple geological information image integration for uranium resource evaluation has been preliminarily established.
From the viewpoint of targets of remote sensing monitoring for mine exploitation and
mine environment and on the basis of image characteristics of the monitoring targets, the authors
analyzed the detection capabilities of this means for different data sources such as high spatial
resolution, hyperspectrum, microwave and thermal infrared remote sensing, and summarized
comprehensively the application situation, existing problems, major research fields and key
technologies. The authors also tentatively put forward some methods for solving these problems in
the remote sensing monitoring of mines.
It is indicated that atmospheric correction for optical remote sensing is absolutely necessary for quantitative remote sensing. The atmospheric correction methods can be grouped into four types, namely, relative correction based on image information, linear regression based on ground spectra, radiative transfer models and composite models. Their advantages and disadvantages as well as their adaptability or effective factors are analyzed in this paper. Some thoughts on the future development of atmospheric correction for optical remote sensing are also put forward in the end of this paper.
Hyperspectral image is a new kind of remote sensing images with the feature of "combining mapping and spectra into one",thus better expressing the subtle differences on the surface of the material through the continuous spectral curve. Hyperspectral images have a wide range of applications in such aspects as classification,unmixing and target detection. With the continuous development of hyperspectral remote sensing technology,anomaly target detection has become one of the most active direction of research because it doesn't need a priori information. Many anomaly target detection algorithms have been proposed. Based on data available both in China and abroad,this paper summarized the research situation and new progress in anomaly detection algorithms. The author first expounded the essence of hyperspectral anomaly target detection and used the basic theory and then analyzed and summed up some representative anomaly detection algorithms in such aspects as the ideas of algorithm,key technology,advantages and disadvantages. On such a basis, the author summarized and described the evaluation method of anomaly detection and discussed the future development trend of anomaly target detection algorithm, with the purpose of finding new breakthroughs in the study of the algorithm of hyperspectral anomaly target detection.
More and more modern high resolution optical remote sensing satellites are being equipped with TDI CCD cameras. Modulation Transfer Function (MTF) is an authoritative means in evaluating the quality and implementation capability of the imaging system. For the purpose of evaluating the satellite criteria in the phase of production, it is necessary to simulate images with the satellite MTF criteria in enough reality. Based on a detailed analysis of the relationship between the satellite criteria and the on-orbit satellite TDI CCD imaging degeneration, this paper gives a method for the simulation of the degeneration process. With the method, a soft ware system was built to simulate the on-orbit imaging process of the designed satellite, which can provide the application experts with a powerful tool to judge the satellite in designing and production.
Taking the interaction between spatial and temporal resolution of remote sensing data into consideration, the authors hold that there is no satellite sensor that can produce images with both high spatial and temporal resolution, and spatiotemporal fusion of remote sensing data is an effective method to solve this problem. This paper introduces main research achievements of spatiotemporal fusion model obtained both in China and abroad. Based on the comparative analysis of the mainstream fusion models, these models can be divided into two categories, i.e., the transformation-based model and the pixel-reconstruction-based model. Furthermore, the authors divide the pixel-reconstruction-based model into mixed linear model and spatial and temporal adaptive reflectance model, and then introduce the basic principles, methods of these models. This paper makes a comparative analysis of the advantages and disadvantages of various aspects of the model. At last, the data, application and scale prospect of spatiotemporal fusion models are put forward.
The Great Dyke in Zimbabwe, which possesses abundant platinum, palladium, gold, chromium, nickel, copper and some other resources, is a major intrusion of mafic and ultramafic rocks formed at 2.5 Ga and one of the key regions for mineral exploration abroad. In order to attain the aim of "going out" for China's mineral exploration and provide basic geological information of geological survey and mineral exploration in the area of the Great dyke, the authors carried out the systematic interpretation of geometric elements and geological characteristics of the Great Dyke in Zimbabwe based on the ETM+ data and verified the division of the magma chamber of the Dyke. Combined with the ZY-1 02C high spatial resolution satellite data, the authors identified and interpreted the shape, lithology, interior structures and mining activities of the Selukwe Subchamber. The results achieved show that, because of the difference between the west and east host rocks, the Selukwe Subchamber underwent deformations of different intensities. The ultramafic layers should be regarded as the major layers for the chromite exploration. Furthermore, the authors have discussed the method of "five scales" of the remote sensing technique in the geological survey abroad and provided the technical support for the remote sensing application.
Spectral reflectance characteristics of rock,soil and vegetation are analyzed based on field data,and a new method
for studying the geometric structure and spatial relationship of typical objects in the spectral feature space is put forward. In
addition, the distribution pattern and relation of typical objects in the spectral feature space within medium vegetation covered
mineral alteration areas are summarized. These conclusions serve as the scientific basis for mineral alteration information
extraction and are also useful to improving the method for extracting mineral alteration information.
The extraction of road from the high resolution remote sensing image remains an open question in spite of the fact that lots of efforts have been made in this area. This paper describes the road feature, road model and the basic idea, analyses the methods for road extraction. The thought and the plans of further research on this subject are also presented.
This paper has compared the effectivenesses of different water body indices which are applied to
identify water bodies based on the MODIS data. The results show that the Combined Index of NDVI and MIR for Water
Body Identification (CIWI) is the most effective index for water body identification when the MODIS data are used.
In calculating CIWI by using the MODIS reflectance data with 0 as the distinguishing value, the constant in the
expression of CIWI is -0.85. It is also shown that the MODIS data are unsuitable for small water body
identification because their spatial resolution is not very high.
Thermal infrared remote sensing is one of the focuses in remote sensing investigations all over the world, and the retrieving of land surface temperature is an important research field. This paper has analyzed the difficulties in the inversion process and summed up several methods for estimating ground absolute emissivity. Three inversion methods and their main merits and shortcomings, their application fields and conditions are described, and the future development trends as well as the key points in the inversion of land surface temperature are also dealt with in the end of this paper.
Based on analyzing the present situation and developing trend of remote sensing, considering the demandof economic and social sustainable development for mineral resources, energy and geological information, and integrating and constructing three RS-based application technology systems and two information service systems under the guidance of geological theory, earth system theory and complexity sciences theory, the author suggests the strategic orientations of geological remote sensing technological development, which include the application technology system for geological exploration and mineral resources assessment, the technological and operational system for monitoring geological disasters and geological environment, the technological and operational system for monitoring mining activities and mine environment, the service system of satellite data acquirement and geological application, and the entirely digitized comprehensive aerial remote sensing system. The objective lies in promoting the transformation from qualitative to quantitative in geological analysis, from single to integrative in technique application, and from data-based to informational in service. The major research fields and their research situation, the existent problems and the key techniques are also discussed in this paper.
In this paper, Wuhan City was selected for case study. Land use information obtained from satellite remote sensing TM image in 2000 and 2005 was used as the main data source, and the GIS technology was employed as the data integration analysis platform. An ecological risk index was constructed based on the varieties of land use, and the systematic sampling method was utilized to make it a spatial variable. After the performance of sampling, the semivariagram analysis and block kriging were conducted to compile the map of ecological risk distribution. The results indicate that the spatial distribution of ecological risk became more uneven in the working area. The level of the ecological risk study area was divided into three levels: the majority of the vegetation and the waters belonged to the low ecological risk area, whereas the urban built-up area and its marginal areas belonged to moderate ecological risk and relatively high risk areas. Spatial distribution of areas of various levels experienced certain extent of changes in the five years.
Funded by Ministry of Land and Resources of China, China Geological Survey and National High Technology Research and
Development Program of China (National 863 Program), the Hyperspectral Research Group of China Aero Geophysical Survey and Remote
Sensing Center for Land and Resources (AGRS) has made remarkable scientific achievements in hyperspectral mineral identification
and mineral mapping since the implementation of the ‘Ninth Five-Year Plan’. These achievements include: (1) the analysis of
features of rock and mineral spectra and influencing factors, (2) mineral identification, abundance estimation and component
derivation, (3) multispectral and hyperspectral data processing and mineral mapping in mid-thermal infrared spectral region, (4)
geological application model, working methods and technical processes, and technology systematic architecture of hyperspectral
mineral mapping, and (5) applications of mineral mapping in such fields as regional mineral survey, geological exploration,
metallogenic and prospecting modeling, plant geochemical detection, mining environmental monitoring, and lunar and planetary
exploration. These achievements are reviewed and summarized in this paper, and the development tendency and research orientations
in hyperspectral mineral mapping are also discussed.
The accuracy of coastline extraction can't be guaranteed by applying a single algorithm,because different types of coasts have different characteristics. The existing researches are mostly focused on the extraction of instantaneous waterline,with the lacking of tidal correction and verification of accuracy. In this paper,the authors presented a method combining coastline extraction with coastal type and tidal correction. MNF rotation,MNDWI,morphology and edge detection were applied to SPOT4 data acquired in Qinhuangdao coastal zone to extract instantaneous waterline. Besides,the coastline was extracted accurately by integrating tidal data to calculate the slope of shoal. Moreover,the verification of the accuracy of coastline extraction was achieved by the GPS data obtained in the same period. The results show that the precision of coastline extraction by the method proposed in this paper is high.
This paper has discussed the application of remote sensing to the monitoring of mineral resources
exploration and mine environment according to the government requirements, and analyzed in detail the problems in
regional monitoring. The remote sensing monitoring technology for the exploration of mineral resources is also
proposed in this paper.
In the light of the application of land and resources and on the basis of the “indicator-simulation-assessment-revised targets-simulation-assessment” model, the authors established an assessment system composed of four components, i.e., software system, hardware system, technical standard and technical method. A relatively perfect assessment and evaluation system based on the application evaluation of land and resources was also built. This research provides new thoughts and new technical system support for the development and data application of satellites in China.
Precision-farming is an essential part of modern agriculture. Precise management could be achieved by acquiring the field information on crops and their growing environment. Field management such as seeding, fertilizing, irrigating and harvesting could be optimized according to the spatial and temporal difference in crop and soil status. Along with the fast development of remote sensing technology, this technology has become an essential component part of precise farming and has been widely used in providing guidance for irrigation, fertilization, weed control, pest control and harvest. Remote sensing can be used to provide basic information of the field (field infrastructure and plot distribution) for farming management as well as to monitor dynamics of crop growing and such relevant environment factors as soil nutrition, soil moisture, crop nutrition and crop pest status in the field. The advances in applying remote sensing in these fields were reviewed and commented in this paper. Based on a review of the current application of remote sensing in precision farming, this paper describes in brief its research situation and gives a vista of its development. It is pointed out that improving the monitoring method, applying new data, integrating multi-source remote sensing data, integrating remote sensing data with agro and crop models and systemization are the key points in this field. Further researches on this field will promote the application of remote sensing in precision farming.
Based on simulations using the SAIL bidirectional canopy reflectance model coupled with the PROSPECT leaf optical properties model, the authors have obtained the vegetation LAI. The FLAASH model is used to ensure the accuracy of atmospheric correction. The LOPEX93 database and the JHU spectral library are employed to identify the input value of the model. The canopy reflectance is the key node to relate the PROSPECT+SAIL model and the remote sensing data, and hence the LAI can be retrieved from leaf biochemical properties, LAD and remote sensing data. In situ measurements of LAI are used to test the simulation results, and the error sources are analyzed.
In this paper, basic characteristics of the wavelet base are analyzed, and a common method for choosing
wavelet bases in compression of the remote sensing image based on wavelet transform is described briefly. Eight
images with different representative ground objects were respectively compressed with four kinds of representative
wavelet bases in a wavelet transform coding experiment. The application effects of these wavelet bases were
evaluated by five methods. The results show that the application effect of wavelet base D (9, 7) is the best. On
such a basis, an improved method for choosing wavelet bases is proposed.
The acquisition of high-spectrum and high-resolution satellite data has experienced a period of more than ten years, with abundant data of high resolution satellite images stored in the archives. Such kinds of information as small faults, bonanzas and stocks (dykes) can be interpreted by these high resolution remote sensing data, which seem to be closely related to numerous metal deposits in normal cases. This method can therefore serve as a means in search for metallic deposits.
A comparison with traditional soil moisture monitoring methods shows that the remote sensing method has great superiority. This paper presents a review of the remote sensing methods currently used both in China and abroad for monitoring soil moisture, which include the reflectivity method, the vegetation index method, the surface temperature, temperature-vegetation index method, the crop water stress index method, the thermal inertia method and the microwave method, with a detailed comparative description of the advantages and disadvantages of these methods. Based on summarizing researches on remote sensing monitoring methods for soil water, this paper evaluated the focal points, difficulties and development trend of this research field. It is held that the thermal inertia method and the vegetation temperature index method are relatively mature methods for soil moisture monitoring. With the wide application of geographic information system, the microwave remote sensing will become the key research direction in this field because of its unique advantages.
Above-ground biomass of forest has great research and application value in the forest ecological system. There are mainly three types of models for estimating above-ground biomass of forest, i.e., forest measuring method, remote sensing method and integrated method. Remote sensing technique has become an important means for obtaining above-ground biomass of forest at the regional scale. There are mainly four types of remote sensing models, namely empirical, ANN, physical and NPP based models. This paper has analyzed and discussed the present methods for estimating above-ground biomass of forest based on remote sensing as well as their advantages and disadvantages. Finally, this paper points out that the integrated method combining remote sensing technique and forest succession model can be generally used to estimate above-ground biomass of forest at the regional scale in future.
Rapid industrialization and urbanization have resulted in extensive changes in land use and coastlines in Bohai Bay coastal zone. For extraction of coastlines and land classification, Landsat TM\ETM images in 2000, 2005 and 2010 were used. Based on the methods of man- machine interactive interpretation and GIS spatial analysis, the authors made a comprehensive analysis of the changes of the coastlines and spatial variation of land use. The extent, speed and spatial variation of the changes of the coastlines and land use were revealed by the combined method of quantitative and qualitative analysis. It can be concluded that Bohai Bay coastal zone had been changed greatly during the last decade. The land and coastlines were growing toward the Bohai Sea by about 322 km<sup>2</sup> and 331.6 km<sup>2</sup>, respectively. Land for housing and other construction purposes increased; unused land and wetlands decreased greatly; Tianjin Port showed the most significant sea-beach wetland change, and the decrease reached 89 percent as compared with the situation in 2000; in other wetlands such as salt pans of Hangu in Bohai Bay the decline rate was the largest (55 percent); the coastline and the land of Tianjin Port had the fastest growing rate during 2000-2005; from 2005 to 2010 the reclamation of Caofeidian Port was the fastest. The main driver of these changes is the result of over-exploitation of human economic activities.
Geometrical registration and threshold selection in remotely sensed image variation detection have been discussed in this paper. The detection of remotely sensed image variation was performed technically by using MATLAB. It is noticed that the general mathematical computing software MATLAB has been extended to a new application area, and a technical means for rapid development of remotely sensed image processing software has been explored.
This paper describes in brief the capabilities and design of HDF 5 (Hierarchy Data Format), such as its structure which is hierarchical in logic and B-Tree in physics, its advantage in straightforward implementation and self-description means of sharing science data among people, projects and types of computers, and its object-oriented specificity. The standardization of remote sensing data can benefit from these characteristics.
Segmentation of gradient images in the traditional watershed algorithm usually has no markers, which is likely to cause excessive segmentation. This paper presents a watershed algorithm based on the label. First, the gradient images are obtained through the reconstruction of gradient by using Sobel operator and, at the same time, the perimeter, area and morphology factors of the region are computed and labeled. Then, the initial image of segmentation is acquired by using the method of distance function icon for determining the seeds and the technique of isoline tracking. Finally, the last result of segmentation is obtained by using an improved method of regional merging. The experimental result shows the effectiveness of the method.
Xishuangbanna is one of the largest tropical forest vegetation and highest biodiversity regions and also an important rubber-producing area in China. This paper has studied the impacts of rubber plantation on the fragmentation of tropical forests and its substitution for natural forests. It is concluded that the rubber plantation in Xishuangbanna shows significant geophysical patterns and high spatial and temporal dynamics. Rubber plantation has had no significant impacts on soil erosion but has evidently accelerated fragmentation, resulting in the homogeneity of landscape. Although rubber plantation has social and economic benefit in a certain degree, it has obviously threatened the biodiversity and stability of the tropical forest ecosystem.
HJ-1 optical satellites are to be launched firstly in small satellite constellation for environment and
disaster monitoring and forecasting. The status of the operation and application has an important theoretical and
[JP2]practical significance for the development of the subsequent constellation. Based on the data characteristics
of HJ-1[JP] optical satellites such as the temporal, spatial and spectral resolutions , the spectra and the swath
width, and considering the requirements of remote sensing application, the authors have analyzed and estamated the
usability of HJ-1 optical satellites comprehensively. It is held that the HJ-1 optical satellites can meet the
principal working needs in China and its neighboring countries in remote sensing application, and will surely have
a wide application potential.
This paper has analyzed the quality of high resolution ALOS satellite images by an empirical analysis method. Based on characteristics of ALOS images, the authors present methods and the flow of ALOS raw images preprocessing. The result shows that the images of ALOS should be used in combination with the images of other satellites when we conduct large-scale, large-area, high-precision and short-cycle land use map updating and dynamic monitoring. This is because the images of ALOS have such shortages as large amounts of work and strict application.
Lack of automaticity and ineffective elimination of seam line exist in the present remote sensing image mosaic. Aimed
at solving these problems, this paper has improved the existing mosaic technology by using valid area. The valid area is obtained
using the automatic tracing method, based on which mosaic of multi remote sensing images is carried out. First, at the geometric
splicing stage, primitive rectangle image participation is replaced by the valid area to carry out splicing. Second, the seam
line is determined using the valid area of the two images, and is eliminated using the whole tone adjustment and the overlapping
area weighting. Finally, in the multi-image mosaic process, the valid area of the resultant image is obtained by collage of the
valid area of two original images. Through the mosaic experiment on two groups of multi remote sensing images, it is concluded
that this technical flow can implement completely the automatic image dodging, and the overall tone is consistent without obvious
seam line in the resultant images.