1997 Vol. 22, No. 4
This paper presents a multiple stages calibration method of CCD array camera,which separate the interior parameters and exterior parameters based on the principle of geometric projection.In the procedure of interior parameters calibration,a multiple calibration approach is developed.The advantages of the method is that it overcomes the related effection between the unknowns,and results a good data accordance and a high precision.Finally,the experiment results certify the advantages of the method.
This paper discusses the three kinds of knowledge based on Markov random field:the distance between the same class images is the shortest;some feature parameters of neighbour pixels are evidence;and images have direction feature.It also presents how the three kinds of knowledge can be acquired and applied in image understanding.Experiments show that these knowledge can help to improve the correct ratio of image understanding.
In order to realize the automatic connection of complex cut lines, this paper takes cross roads as examples and presents an automatic connecting algorithm of cut lines. Experimental results show that the algorithm opens a way to improve the automatic level for geometic figure processing.
This paper discusses the principles and new method of remote sensed image analysis for theme extraction from imaging spectrometer image. The image fusion approach is proposed. The experimental effects of these methods are briefly introduced. The academic characteristics of those methods are pointed out.
The algorithm presented in this paper has theoretically solved the problem of model distortion and analyzed the visual difference caused by display resoultion. Also the M Buffer method to deal with match and 3-D hiding is proposed. The speed of computation is raised substantially. The quality of image is strengthened and the application in geomorphologic research becomes more suitable.
A framework of spatial data mining and knowledge discovery is proposed.The concept and theoretical model of spatial data mining,knowledge types,methods suitable for knowledge discovery in spatial databases,the architecture and development strategy of the spatial knowledge discovery system,etc.,are presented and described in the framework.The future directions of spatial data mining and knowledge discovery are discussed at last.
Introducing Intranet mechanism into U GIS design,this paper puts forward a new GIS architecture with four platforms driven by spatial task servers.The new hypermedia data structure,system network requirements, and key points in the system have been expounded in the paper also.As pointed by authors,the new system not only focuses on sharing and transmitting information,but also emphasizes reliability and security.So surely it can be widely used in the future.
To fully expolit the advantage of precise GPS carrier phase measurements the integer ambiguities in the observations must be resolved.There are several ambiguity resolution techniques developed in the last decade.A common criterion used in these techniques to select the best set of ambiguities is the minimum quadratic form of the residuals.Because the observations contain various types of errors,the resolved integer ambiguities are with some degree of uncertainty.To obtain a reliable result the selected ambiguities must be tested against the other possible ones,which is called the validation of resolved ambiguities.There exist several approaches,each of which,however,has some limitation and shortcomings.This research has developed a methodology based on the concept of model discrimination.Given type Ⅰ and type Ⅱ errors two boundary values are derived.The solution with the minimum variance factor is validated using these two values.Compared with the existing approaches,the proposed one is theoretically sound,and the decision made based on it will have a clear indication of confidence in accepting the resolved ambiguities and rejecting the others.
The purpose of the paper is to present spherical harmonic analysis for determining the Earth's gravity field model from satellite gravity gradiometry data. And the mathematical model which transforms the spherical harmonic expansion coefficients of some gravity gradient component to that of disturbing potential is derived. Moreover, simulation test results show that it is very effective and practical.
In the paper,the intrinsic structure of the gravity field is first introduced into the study of the normal ellipsoid's interior.After the further relationship among the intrinsic geometric properties is built,the relation between the geometric properties and physics of the interior is presented,which follows,the basic differential equation on the condition of quasi-equlibrium is set up,and finally the method to determine the intrinsic geometric poperties and density of the ellipsoid is given.It's shown that Wavre formula and Clairant equation which are on the condition of equilibrium and ellipsoidal approximation can also be derived in this way.
The characters of auto-regressive model and regressive model are analyzed. The idea of forecasting deformation of rockfall body by linear synthetic model is given and the shortage of auto-regressive model and regressive model is modified. The treatment to practical data expresses that it has a special suitability.
On the basis of program practice concerning several approaches to construct buffer zone for cartographic and GIS data handling. Analysis and comparison between method of angular bisectrix and method of circular arc are analyzed. The former often brings out graphic anomalies which can require further multi-criteria judgement and corresponding correction processing. That would make this method difficult to be used.As the opposite with the method of angular bisectrix a circular arc method for construction of double parallel lines of buffer boundary has been developed. The latter method is based on the enhanced judgements (convex/concave judgement, controllable chord to arc approximation) guaranteeing the width equality to the utmost extent. The core issue is the treatment of circular arc method which is based on the double mathematical models: the geometric model for constructing the double parallel lines and the relation handling model for detecting the islands and overlapping areas. Both islands and overlapping areas have symmetric structure properties: islands of left bound line appears in anticlockwise,but overlapping areas clockwise. For right boundary line the situation is completely opposite. The island polygons should serve as components of final parallel lines or buffer boundaries. At last, scheme of construction buffer zones for tree structure of line objects and complex network configuration is proposed.
This paper presents a new method to research the wear of cutting tool based on fractal theory and discusses the fractal characteristic and structure of the flank wear of cutting tool in theory experiment and caculation. Based on fractal dimension, the relationship between the cutting velocity and the fractal structure of cutting tool wear has been built.