The paper discusses the interaction of short surface waves with shearing and converging current.
On the basis of the spectral perturbations caused by the interaction, the influences of the interaction on the
ocean surface wave spectral density and gradients are analyzed. A two-scale electromagnetic scattering
model explains not only the interaction between short-wave and radar backscatter, but also the interaction
between long-wave and radar backscattering. Then SAR imaging mechanism of ocean fronts is derived. In
SAR images, the scale of ocean fronts is 2~3 orders larger than that of sea waves. Most of wave
information is filtered out by the 2-D spatial spectrum analytics. Then the characteristic information of
ocean fronts is extracted by digital image processing technology. Thus, information processing means by
which characteristic information of ocean fronts can be extracted from SAR images is constructed.
With the development of space exploration, synthetic microwave remote sensor is playing more and more important role in the field of microwave remote sensing. A synthetic microwave remote sensor,also can be named multi-mode micowave remote sensor(MRS), is composed of several single-mode remote sensing subsystems which can work together fluently and share as many resources as possible, which key component is the control and communication system. In this paper, a control and communication system of such remote sensor is introduced in detail.
Change detection is playing more and more important role in remote sensing information processing. However, there are two aspects of shortcoming in existing change detection algorithms. One is that too large amount of raw data is usually needed to implement the change detection. The other is that it is sometimes difficult to acquire enough amount of quantitative information. In this paper, the runway in airport is detected by taking Hough transform in single-band images. The region of interest is then located by region-growing. After a coarse step of calibration, a judgement is made on whether there is change occurring within ROI based on the edge-correlation. Finally, the elastic mask matching procedure is adopted to make an explanation to the changes detected. Satisfactory results are obtained in the experiments.
In the process of satellite sensor imaging, the received message (digital code)have been impacted and changed as the reason of atmospheric absorption and scattering. This impact will lead to extract fallibly and also reduce the accuracy of Parameterization Methods for Remote Sensing Data. The fact derived from studies and conclusions shows the atmospheric correction is an important procedure and component in the remote sensing methods and applications. This paper gives an introduction of a SpatiallyAdaptive Fast Atmospheric Correction(ATCOR2) including fast atmospheric correction algorithm, the structure of modules and calculation flow. Also, the Look-up Table presented the atmospheric profiles and catalogues would be recommended in detail. Meanwhile, a sample by using ATCOR2 for atmospheric correction has been given with a part of Landsat TM in the Source Region of Yellow River.
Remotely sensed data are so large that they can not be dealed with by human brains. Therefore,
it becomes increasely important to find a method to get information automatically, quickly, efficiently from
remotely sensed data. The technology of Data Mining was put up with in 1980' s, and it has been used in
many fields, such as finance fields, insurance fields, retail fields, medical and justice, etc. Data mining is
the non-trivial process of identifying valid, novel, potentially useful, ultimately understandable patterns
from huge volume of data. The spatial data mining is developed on the base of it. In a sense, spatial data
mining resolves the problem of abundant data that human brain cannot be competent with. Furthermore, it
can be used in artificial intelligence and pattern recognition fields. Spatial data mining differentiates from
general data mining. Because Spatial data mining must consider the topology relation between the
neighboring object, the direction and distance, etc. On the contrary, the general data mining consider
every element in the database is independent. Nowadays, although the technology of the spatial data
mining develops very quickly, it has not matured. There still are many things for us to do, especially, the
extraction of the hedge and the feeble information from the remotely sensed images. This paper provides
the background of spatial data mining, the general process of data mining, common algorithms, language
and prospect.
At present, Web GIS is one developmental tread of Geographic Information System.The paper described GIS and Web GIS. Through analyng is the principle of Internet GIS, several implemental ways of Web GIS technology are described. Then, application of Web GIS technology in the electrical system is introduced.At last an effective scheme, to which the design of strudure and function are introduced is given to develop Web GIS of Power Station.
Vegetation is one of the key factors that affect the measurement of soil moisture with radar. The
degree to which vegetation affects the determination of soil moisture depends on the mass of vegetation and
the wavelength. The most important task of soil moisture microwave remote sensing is to develop suitable
vegetation scattering models which can include the effect of soil under the vegetation. The development of
these models can help us understand thoroughly the complex interaction among all scattering factors,
quantitatively analyze the sensitivity of backscattering coefficient to different scattering factors, get soil
moisture information by inversion. Generally, there are three different kinds of vegetation scattering
models: empirical, theoretical and semi-empirical. Each kind of model has its own advantages and
applicability. Reviewing the process of vegetation scattering model is beneficial to our selection of optimal
model in a given research.
With the expansion and deepenning of GIS application, the data amount of GIS is increasing constantly, and the data model of GIS is more and more complicated. How to store and manage the magnanimity data and how to offer a high-efficient datum index mechanism become key problems of GIS field. The data index can solve the issues how to visit, draw and analyse the necessary data fast from the magnanimity data.The approaches of storage and index for spatial vector data affect directly property of GIS, so it is helpful for application and research of GIS to understand their development. This paper introduces the development of approaches in storage and index for spatial vector data, and summaries their characteristics.
The L-band polarimetric data of SIR-C system are calibrated by Whitt' s polarimetric SAR calibration algorithm using point targets in this paper. The image data that are calibrated by SIR-C calibration group are considered as theoretic data and from this image three point targets are selected and used in the Whitt' s algorithm to get necessary calibration parameters. Then these calibration parameters are used to calibrate the uncalibrated image data. Finally the calibration results of Whitt' s algorithm are compared with the results obtained by SIR-C calibration group and its performance is verified. The two distinct advantages of the technique are that: (1)almost any three targets can be used, and (2)no assumptions are made about the magnitude of the distortion. And this technique is applicable to both laboratory and field measurements, with the known targets being chosen according to the application.
Image fusion is currently an active research field. The objective of image fusion is to combine
information from multiple images of the same scene to achieve inferences that cannot be achieved with a
single image or source. Image fusion refers to the techniques that integrate complementary information
from multi-image sensor data such that the new images are more suitable for the purpose of human visual
perception and the computer-processing tasks such as segmentation, feature extraction, and object
recognition. There are two essential requirements for image fusion: (1) pattern conservation: important
details of the component images must be preserved in the composite image; and (2) spurious elements
avoidance: it must not introduce any new pattern elements or artifacts that could interfere with subsequent
image analysis and reconstruction. Pixel level fusion is low-level fusion which uses basic information. In
this paper, a few image fusion methods are discussed and compared, and image fusion is classified based on
space domain and transform domain. Performance evaluation of multi-sensor image fusion is a key problem
in image fusion. This paper discusses performance evaluation of image fusion using cross entropy too.
The present theories and methods on radar image ortho-rectification home and abroad,and the radar imaging priciple were analyzed synthetically in this paper.The Range-Doppler theory was introduced especially and applied to SAR image ortho-rectification and realized with programs on the computer.At last,an experiment was made with ERS-2 product and the result showed the ortho-rectification method had an higher accuracy and an good result image.It could be applied to SAR image geomatric processing.
