The Application of the ways of systematic theory and information Theory to Marine Satellite Remote Sensing
Li Tie-fang Zhongshan Univ., P. R. China
Yi Jian-chun Univ. of Southern California, U.S.A
Abstract
The authors analyses the transmitting process of the information obtained from marine satellite Remote Sensing, and regards it as a complex system composed of several random sub-systems such as atmosphere, water-body, seabed and the boundary of water-air, and the transmitted information has the features of grew and fuzziness, so as to limit the use of Remote Sensing data by physical or statistical model for extracting the informations of water body. The paper raised a valid way to extract marine information based on the theories of grey system and information.
- To use filter method for separating sub-systems;
- To use the idea of entropy (average information) to simplify physical model;
- To introduce the relative degree and correlation function of grey mathematics for evaluating the result of application of information extracting model, and for establisbing a relevant formula;
- To use the feed-back of information for controlling and interpreting image data on the basis of oceanology, geo-science, biology and expert knowledges.
The introduction of these methods have greatly improved the applied effects of remote sensing.
Information has been regarded to be the third resources next to living beings and minerals which human being is developing and using, so the information of marine Remote Sensing are also taken seriously as a new marine resource. Based on our research for years, we developed some ways for analyzing, understanding and extracting the information obtained from Remote Sensing.
I. The systematical analysis of the transmitting precess of marine Remote Sensing information.
The transmitting process for marine Remote Sensing information is shown as fig. 1.
The information is transmitted through several different sub-systems such as atmosphere, water-body, and the boundaries of seabed and water-air and so on. The transmission function of spectral of each sub-system can be described as “H”, and then the spectral signal Ei received by the sensor of satellite can be written as
Ozone Water vapour Suspensate Wave, Current, Undersea landform Chlorophyll Silt content Water depth Suspensate Bottom materias Underseas landform
Fig. 1
The fig. 1 shows that the system is composed of several sub-systems with random medium and complex boundary which are reciprocally associated; Each sub-system is controlled and influenced by the changes of time and space, so the features of remote sensing information are as follows:
- Plenty of water information are transmitted;
- The matual influence of sub-systems make various sorts of information overlap and interfere one another , so as to become hazy;
- Both the indefiniteness of spectral interpretation and the availability of time and space made the system carry the feature of grey.
As the above reasons, it is difficult to get exact physical parameters for establishing any numerical calculation model. A simple model may be used to replace formula (1) by existent conditions of information resources available. Suppose each sub-systems is reciprocally independent and their information are simple overlap without changes of time and space, the signal L ( ) received by sensor at the height Z0 can be written as (Crack nell, 1981).
In actual application, the establishment of the numerical function of formula (2) is still difficult, because it is hard to get the parameters of an object. Therefore, at present for its use it mostly is to establish a semi-experienced statistical model of formula (2) in the practice, which is
Here : Y : the value of parameter measured over the sea at the same
time as satellite passing through.
a and b : regression coefficient
F [ ]. the Remote Sensing data processed by some ways.
If monitoring points are so few that the number of sample could not weet the rule of large sample of statistics in a sea area with large changes of time and space, the calculating error of this formula will be too large to use.
