20 August 2005, Volume 20 Issue 4

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  • SUN Li, CHEN Xi, BO An-ming,FENG Xian-wei,MA Ya-qin, WANG Deng-wei
    Remote Sensing Technology and Application. 2005, 20(4): 315-3620. https://doi.org/10.11873/j.issn.1004-0323.2005.4.315
    Abstract ( )   Knowledge map   Save

    In this paper, the hyperspectral data of cotton canopies grown in north Xinjiang at the main growing stage under water stress are derived by using an ASD spectrocoparator made in USA, the rededge integral areas are used to estimate the total N content in leaves of cotton canopies, and the analyzing method based on the spectral position variables is derived from the first differential spectral data. An analysis on the correlation between the red-edge integral areas (used as the independent variables) and the total N contents in leaves of cotton canopies (used as functions) is carried out so as to develop a mathematical model about the correlation between the red-edge integral areas and the total N contents in canopy leaves of cotton variety of Xin Luzao No.6. The correlations between the chlorophyll contents and the total N contents in separate leaves of cotton canopies under the different irrigation water volumes are researched. The results show that there is a significant positive correlation between the chlorophyll content and the total N content in leaves of cotton canopies (R=0.8723, n=39), and the data of chlorophyll contents can be used to effectively estimate the total N content in separate cotton leaves; there is also a significant correlation between the red-edge integral areas and the total N contents in leaves of cotton canopies,and the correlation coefficient is 0.7394 (n=40). The total N contents in canopy leaves of cotton varieties of Xin Luzao No. 6 and No.8 can be accurately estimated by using the developed model, and the values of RMSE are 0.3859 and 0.4272 respectively. It is considered that there is a potentiality to use the variables of red-edge integral areas for predicting the total N contents in leaves of cotton canopies, and it is also feasible that the data of displacement and change of red-edge extent can be used to recognize the moisture stress of cotton plants if a rational recognition system is develop. The conclusions of the study are as follows: (1) The physiological and biochemical properties of both cotton leaves and canopies are changed with cotton growth; (2) There is a significant correlation between the chlorophyll content and total N contents in cotton leaves (R=0.8723, n=38), and the total N contents in cotton leaves can be estimated by a mathematical model; (3) The analyzing method based on the variables of spectral position of "red edge" of cotton leaves, derived from the first differential spectral data, reveals that the change extent, shape and area of the "red edge" contain the information of various wavebands, and the capability of predicting Nnutrient in cotton leaves and canopies can be provided by using the developed model based on the variables from these wavebands; (4) It is reveals that the moisture supply is sufficient, the N metabolizing in cotton plants is hearty, the cotton plants grow luxuriantly, and the red edge of cotton leaves shifts towards blue light if the chlorophyll content in cotton leaves is high. It is feasible that the data of displacement and change of red-edge extent can be used to recognize the moisture stress of cotton plants if a rational recog-
    nition system is develop.

  • YOU Hong-jian, SU Lin, LI Shu-kai
    Remote Sensing Technology and Application. 2005, 20(4): 381-385. https://doi.org/10.11873/j.issn.1004-0323.2005.4.381
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    3D building information is important geospatial information and it can be widely used in urban planning and management. Airborne laser scanning range data can be used to reconstruct the 3D buildings owing to its ability to acquire 3D information of terrain. A method to extract building 3D information automatically based on spare laser points acquired by airborne laser scanning system which is developed by China is presented in the paper. 3D position of laser sample points are calculated first using laser range, altitude and platform position, then we can generate digital surface model (DSM) by interpolating the raw sample laser points. Digital terrain model (DTM) of the urban is calculated based on the histogram of height of laser points. Combining DSM and DTM, we extract the contours of buildings and then the contours of the buildings are regulated to reconstruct the 3D information because the building generally has a regular shape. A practical regulation which is composed of contour following, polygon approaching,grouping based on azimuth and regulating edge is also presented. A processing test demonstrates that the proposed method is feasible.

  • CHEN Fang, NIU Zheng, LUO Cheng-feng, WANG Chang-yao
    Remote Sensing Technology and Application. 2005, 20(4): 386-392. https://doi.org/10.11873/j.issn.1004-0323.2005.4.386
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    The characteristics of spectrum are very effective to recognize different kinds of objects. The figures of different objects' reflectance curves are quite different. Based on comparison of reflectance curves' igures, the kinds of different objects could be correctly distinguished. In practice, because of the complex nfluence of atmosphere in radioactive transfer, the reflectance curves computed from remote sensing image re different from those measured from the earth' s surface directly. For the reason, errors of the object ecognition would be caused. The paper analyses the differences between the two kinds of reflectance urves and defines their shape parameters to reflect their characteristics of the figure .Based on the shape arameters and spectral library, a new algorithm has been carried to reduce the difference caused by atmospheric radiation, and recognize objects automatically. The shape parameter curve well describes the figure haracters of objects, and more detailed information could be acquired by the new method. The algorithm as been applied for the object recognition of TM images,and the total accuracy reaches 88.96% in the test egion.

  • SONG Xiao-yu, WANG Ji-hua, LIU Liang-yun,Huang Wen-jiang, ZHAO Chun-jiang
    Remote Sensing Technology and Application. 2005, 20(4): 393-398. https://doi.org/10.11873/j.issn.1004-0323.2005.4.393
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    With its combination of good spatial and spectral resolution, visible to near infrared spectral maging from aircraft or spacecraft is a highly valuable technology for remote sensing of the earth' s surface. In practice, it is desirable to eliminate atmospheric effects on the imagery, a process known as atmospheric correction or atmospheric compensation. At present, there are many atmospheric correction software packages for imagery atmospheric correction, such as ATREM(Atmospheric REMoval program), ACORN(Atmospheric CORrection Now) and FLAASH(Fast Line of Sight Atmospheric Analysis of Spectral ypercubes). In this paper, the latest version of FLAASHatmosphere correction code derives its physicsbased algorithm from the MODTRAN4 radiative transfer code was introduced.and some comparisons of ith FLAASH-processed AVIRIS data, including results obtained using different processing options wereshowed. A preliminary evaluation to FLAASHalgorithm was done in this paper and the result showed thatthe new automated spectral recalibration algorithm, which has been incorporated into FLAASH, is an extremely valuable addition. It improve the quality of the output reflectance cube for measured radiance datacontaining wavelength calibration errors and it also can be used as a tool to measure varying wavelengthshifts in corss-track spatial dimension of an image, such are found in data from the AVIRIS sensor.

  • DONG Li-xin, KONG Jin-ling, WANG Wen-ke,MA Ming-guo, LI You-hong
    Remote Sensing Technology and Application. 2005, 20(4): 399-403. https://doi.org/10.11873/j.issn.1004-0323.2005.4.399
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    The study of LUCC in typical and frangible region is the important content of the territorial research. The Source regions of Yangtse, Lancang and Yellow River is the state natural protective regions.The eco-environment is very frangible and sensitive in this area. Give an example of application of Maduo county, this article have systematically studied the LUCC and the influence on Landscape Pattern and discussed the course of LUCC in the region based on RS and GIS Methods. The result will establish the foundation of the territorial research and provide the decision-making basis for the environment protection in the region. Key points include that①During the 10 years, the areas of grasslands, marshes and water is sharply decreasing, the proportion of marshes have decreased 36.63%. The number of lake which the area is more than 6 hectare have half decreased. The sands, the bare-land and the pickled-land is sharply expanding. The degenerate and desertification of grassland is serious.②The transform of style among the grassland, the sands, the bare-land, the water, the marshes and the pickled-land is obvious.③The index of diversity and evenness and the extent of Landscape' s heterogeneity have been improved. The lands are
    diversifying and evening; The dominance of the sand land and the bare-land have been increased.The dominance of the water, the marshes and the grass-land have been decreased; The overall fragmentation of lands is tend to decrease,while the fragmentation of the sand land and the marshes is tend to increase.④The integrate-dynamic extent of land use is 0.98. The area of the grass-land、the bare-land, the marshes and the sand land is sharply changing.⑤The LUCC of the regions will profoundly impact the eco-environmental evolution process and the self-restraint and supply of water resource in the Source regions of Yangtse, Lancang and Yellow River.

  • WANG Lin, XU Han-qiu, LI Sheng
    Remote Sensing Technology and Application. 2005, 20(4): 404-410. https://doi.org/10.11873/j.issn.1004-0323.2005.4.404
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    The shoreline changes in Xiamen Island with its surrounding areas of SE China from 1989 to 2000 have been detected using remotely sensed data. Three Landsat TM/ETM+ images of 1989, 1995 and 2000 have been used for this study. The MNDWI (Modified Normalized Difference Water Index) with appropriate thresholds were used to extract the water information from the original images. However, the highlighted water also contains some information about inland waters, such as reservoirs, lakes and so on,which are unwanted in this study. Therefore, those inland waters should be further masked out from the MNDWI images. As a technique of change detection, the Red Green Difference Image is employed to reveal the shoreline changes and the changed area was thus calculated. The final results indicate that the sea area of Xiamen has been reduced by 7.54 km2during the study years. This was largely due to the rapid expansion of urban and fishing pools. Furthermore, the speed of the reduction has been speeded up in the last five years from 1995 to 2000. It reflected the urgent land demand of the urban construction and economy development in Xiamen during the years of 1995~2000.

  • MO Deng-kui, LIN Hui, SUN Hua, XIONG Yu-jiu, LIU Xiu-ying
    Remote Sensing Technology and Application. 2005, 20(4): 411-414. https://doi.org/10.11873/j.issn.1004-0323.2005.4.411
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    As the main data sources for land cover and land use, high-resolution imagery provides a good basis for extracting land cover and land use information. Going far beyond the methodical limits of pixelbased and manual interpretation approaches, multi-scale image segmentation , classification based fuzzy logic and object-oriented image analysis approaches are used for extracting information from remote sensing data. This paper presents a snapshot of work to extracting information in Zhuzhou city between country and urban. It allows the segmentation of an image into highly homogeneous image objects in any chosen scale 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. The result of land cover information extraction is promising and the precision of classification is wonderful. It is obvious that such new image analysis approach offers a satisfying solution to extract information quickly and efficiently.

  • SONG Zhi-rui, MA Yi-lin, TANG Chun-hua
    Remote Sensing Technology and Application. 2005, 20(4): 415-419. https://doi.org/10.11873/j.issn.1004-0323.2005.4.415
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    Through of use airphotoes and satellite pictures of multi-time and multi-wave bands and the
    newest TM+ETM photograph,this paper detailed studied the evolutionary characteristics of the Yangtze
    River course in Jiangxi section according to take the methods with eye-sighting explanation and picture dis-
    posal technique in computer,as well as analyse the historical data.The evolutionarg process of the Yangtze
    River channel in Jiangxi Province has been known basically,include of the important transitional events
    since the Qing Dynasty.But it has been evolving which shows mainly sapping and depositing of the trunk
    stream,that is,the riverbank line is scoured and lateral erosived and recessived,the side shoal is silted and
    inflated,the continent and the shoal in the center of river and the shoal patch are increase-silted and inflat-
    ed and died out and floated, and the river bed is fouled, etc.It provides science evidence for studying the
    genetic background of waterlogging hazards and the damage causing,as well as preventing and governing

  • FU Chun-xia, WU Ji
    Remote Sensing Technology and Application. 2005, 20(4): 420-424. https://doi.org/10.11873/j.issn.1004-0323.2005.4.420
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    Soil moisture and ocean salinity are two important parameters for water cycle and climate change studies. The best way to measure these two parameters is to use microwave radiometer at low frequency band, such as P or L band. However, at these frequencies, the physical size of the antenna is very big in order to reach a modest spatial resolution. To scan such kind of large antenna is also difficult. Further more, if the antenna beam become very narrow, the integration time of each resolution cell will become small which will lead to poor measurement sensitivity.
          To overcome all difficulties mentioned above, the synthetic aperture microwave radiometer technology is proposed. This technology uses both thinned array antenna and electrical scan. Therefore not only the large/heavy antenna aperture problem is solved, but also the integration time will not be related to the spatial resolution any more. It is therefore a very promising technology for low frequency band microwave radiometers and can be implemented for soil moisture and ocean salinity applications.
         The basic concept of synthetic aperture radiometer is to measure spatial frequency of the scene instead of the image itself. The output of the spatial frequency is usually called the visibillity function (VF).While all the spatial frequency outputs or VF are measured, corresponding to all baselines with different length and orientation, the image of the scene is a mathematical transformation of the VF.This paper put forward an interpolation method based on wavelet transform, whose role is to give a modification to the Fourier image reconstruction arithmetic of 2-D microwave synthetic aperture radiometer.

  • WU Fan, WANG Chao, ZHANG Wei-guo, ZHANG Hong
    Remote Sensing Technology and Application. 2005, 20(4): 425-429. https://doi.org/10.11873/j.issn.1004-0323.2005.4.425
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    Microwave radiometer image contains information of ground brightness temperature.For its low resolution and unclear object' s shape, it is not convenient to be studied. Something like SAR, synthetic aperture microwave radiometer also has the characteristics that it can acquire images during day and night and with all weather conditions. Moreover, it has the ability to“penetrate”surface soil or vegetation under lower frequency region. Contrast to the radiometer image, the optical images have higher resolution and contain different information. To integrate some features of these two kinds of images, some transform schemes, such as intensity-hue-saturation (IHS), principal component analysis (PCA) and wavelet transform (WT), were applied to merge the airborne synthetic aperture microwave radiometer and ETM+ images. The experiments show that the wavelet based transform method not only can preserve the spectral information of ETM+ image well, but also can preserve the texture information from radiometer image.In conclusion, the WT approach has the best potential among those three methods.

  • HAN Zhao-hui, LEI Li-qing
    Remote Sensing Technology and Application. 2005, 20(4): 430-434. https://doi.org/10.11873/j.issn.1004-0323.2005.4.430
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    We analyzed three existing methods for improving azimuth resolution for distributed SAR system in this paper: to extend equivalent Doppler spectrum in time domain, which improves resolution while leads to spectrum overlapping and worsen results; to improve spectrum utilization and realize full-aperture imaging, which results in considerable computational complexity; to carry out spatial filtering by means of statistics and estimation, which enlarges imaging area while maintains theoretical resolution and results in amazing computational complexity for pseudo-inverse of matrix. In view of the shortcomings of these methods, we proposed a spatial frequency filtering approach to improve the synthesized spectrum to overcome them. We presented computer simulations to validate the proposed method.

  • XU Guo-qing, SUN Bo
    Remote Sensing Technology and Application. 2005, 20(4): 435-438. https://doi.org/10.11873/j.issn.1004-0323.2005.4.435
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    The servo system is one of the most important parts in the tracking radar system. It moves the radar beam to minimize the pointing error between the axial direction of radar beam and the object being tracked. A modern adaptive bandwidth digital control servo system of the tracking radar based on stepper motor is presented in this paper. The servo system controls the movement of the radar system in Cartesian system precisely by digital signal processor, which ensures that the radar system can get high closed-loop control accuracy of target tracking by its safe and steady open-loop control. By using digital control of the system, the empirical formula of target tracking and principle of fuzzy control can be combined to harmonize the system bandwidth and tracking accuracy and make the system run in optimal state, according to performance of angular orientation sensitivity. The servo system of tracking radar based on stepper motor is simpler and more reliable in contrast with the one based on alternating current motor or dc motor. It can find application in the mini-system which does not ask for the capacity for high speed tracking.

  • ZHANG Dong, GUO Wei
    Remote Sensing Technology and Application. 2005, 20(4): 439-442. https://doi.org/10.11873/j.issn.1004-0323.2005.4.439
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    ChangE-1(CE-1) will be the first satellite of China in lunar orbit. Its radiometer operates at 3.0,7.8, 19.35 and 37 GHz in a nadir viewing mode. By now, the pre-launch experimental CE-1 Microwave Radiometer is developed. In this paper, an experiment on the ground calibration of 37GHz channel is carried out. First, the linearity and sensitivity of its receiver is obtained to be 0.9999 and 0.17 K, respectively, and satisfy the performance requirements, so CE-1 Microwave Radiometer can be calibrated through high and low temperature points: the high temperature point is from the matching load, the low one is from the liquid nitrogen refrigerated calibration blackbody target. Moreover, to amend the influence by the transmission network, the modified hardware radiative transfer model is built up. The antenna temperature calibration equation, which accounts for losses and mismatch, is derived finally based on the model and the error of calibration is less than 0.85K. The results provide a constructive reference to the further
    development of CE-1 Microwave Radiometer for launch.

  • CHAI Rao-jun, MA Cai-wen
    Remote Sensing Technology and Application. 2005, 20(4): 443-446. https://doi.org/10.11873/j.issn.1004-0323.2005.4.443
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    In this paper, characters of high moving puny targets have been analyzed thoroughly in order to extract them from backgrounds for template matching. Then linear prediction contributes to decrease computing time by 90%. After that take even gray difference to evaluate the similarity of target sub-zones and adjustable templates. Experiments results prove this algorithm is fast, stable and efficient.

  • KANG Qing, YU Rong, ZHANG Zeng-xiang, ZHAO Xiao-li
    Remote Sensing Technology and Application. 2005, 20(4): 447-454. https://doi.org/10.11873/j.issn.1004-0323.2005.4.447
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    In this paper, the national/international developments in study of remote sensing application of soil salinization recently are reviewed and summarized, including features and interference of soil salinization information in remote sensing, sources of remote sensing data, methods of image processing, and focus of remote sensing applications in this field. By means of remote sensing and conventional methods,such as aerial and satellite remote sensing, ground-based inspecting and chemistry analyzing, geographical methods, and historical data studying, etc., kinds of data about soil salinization can be got. Good quantified results have been achieved from data integration and synthetic analysis, supported by GIS tools, by some specialists and scholars, in recent years.

  • QU Jian-sheng, GAO Feng, CHEN Ling-dong
    Remote Sensing Technology and Application. 2005, 20(4): 455-459. https://doi.org/10.11873/j.issn.1004-0323.2005.4.455
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    The observation activities have come into a new period of integrated observation. It is needed to establish a coordinated observation system for scientific research, data achieving and police making. Based a introduction to the Integrated Global Carbon Observation Theme Project of Integrated Global Observation Strategy, the paper analyzes the foundations, requirements of polices, technologies and equipments,which are all necessary for a new system of integrated global carbon cycle observation. And then, the goals and tasks of the new observation system are put forward. The future tasks of the system, which include (1) the magnitudes, distributions and changes of the carbon pools; (2) magnitudes and distributions of the carbon fluxes; (3) process of the carbon cycle, are addressed at the end.