Linear Target Feature Extraction And Its Airport Target Recognition Applications

Along with the widely using of remote sensing technology in civil and military fields, such as resource reconnoitering, the GPS, recognition of airports and naval ports, the efficient extraction and recognition of the remote sensing image objects has been attached great importance to, which is very important for the application of remote sensing images as well as for the development of remote sensing technology itself. As plays an important part in the remote sensing technology, the auto-recognition of remote sensing image objects by computer is a hot field and a key technology in computer vision. It has attracted many researchers in different fields to work over it broadly and deeply. However, as a new and difficult field in computer vision, there are still many problems to be studied and resolved ulteriorly.Shape is an essential character of objects and recognition through shape is an effective method in the computer-aided auto-recognition of remote sensing image objects. Among various objects with different shapes, there are linear objects in large quantity, so the research on the auto-recognition of linear objects has significant academic sense and practical value.This paper analyzes several expressions about shape as an inhere character of objects, and discusses each description of shape based on area and edge. At the same time, based on the character-selecting principles of recognition and the fact that many important objects in remote sensing images behave linear and the practical need of recognition of these objects, we point out that the edge information represents the image content and raise the method of character extraction and recognition through linear shape.This paper studies the feature extraction of linear objects in remote sensing images and the computer-aided auto-recognition of airports. After discussing the basic knowledge of remote sensing and the interferential factors in remote sensing images, the paper analyzes the pre-processing technology that is fit for shape analysis and expression and edge feature extraction based on the requirement of object recognition. In shape analysis, we get feature units of shape, that is, arc segments and straight-line segments through segmentation and identification of digital curves and the following combination of the same features, and present a new method of object expression and recognition based on straight-line segments. Because straight-line segments represent the edge structure of the straight linear objects and meet the three properties as moving, rotating and scale inflexibility, it's effective for describing the shape of runways of the airport. We can achieve the recognition of airport through describing the shape of it with straight-line segments and distinguishing different objects with the length of the lines.Finally, we design a recognition system through straight linear shape based on the result of shape analysis and the practical requirement on application of remote sensing images. After histogram transform, enhancement, smoothing, pre-segmentation, edge extraction and thinning, we get an image with clear edges. After extracting of feature units, we describe the shape of airports with straight-line segments and distinguish different objects with the length of the lines, which can achieve the computer-aided auto-recognition of airports. The experiment results prove its validity.