遥感数字图像处理技术在地质填图中的应用研究

发布时间：2019-02-11 14:22

【摘要】：地质填图是指对特定区域的地质年代、地层、构造、矿产资源进行定义、描述、勘查的过程,其比例尺的选取可以根据实际情况选定,最常用的是1:500-1:50000。传统地质工作对某些区域(如我国喜马拉雅山脉)进行实地勘查时,由于受这些地区地理环境险峻、气候恶劣等因素影响,会存在勘查盲区。传统地质填图方式中,地质工作人员通常选取特殊地质点进行填图,如采用1:200000比例尺进行填图时,每两平方公里的范围内选取一个地质点进行观测,这就存在盲区,无法保证填图的准确性。用人工方式填充一幅1:200000地质图时,需一个地质大队(200-300人)工作两年时间,耗费巨大。数字地质填图方式,借助遥感数字图像对整个区域进行全面详细、无盲区地观察,有利于地质工作人员从时间和空间上对整个地质填图区域有一个宏观的认识和把握,使得地质填图成果更加贴近客观实际。近年来,随着遥感数字图像处理技术在地质填图中不断发展进步,地质工作者越来越意识到其重要性和不可替代性。目前,遥感数字图像经过相关处理方法变换后作为传统方式地质填图时的参考。采用遥感数字图像处理技术进行地质填图过程中存在许多问题。例如,在进行遥感数字图像预处理时,存在像素点亮度值丢失、彩色合成图像颜色偏蓝、对比度不适中、不利于目视判读等问题,导致图像失真。由于不同卫星的不同图像采集设备对图像中有效像素的影响是一致的。例如,对不同波段的图像,如果偏强,则所有有效像素全部偏强；如果偏弱,则所有有效像素全部偏弱。商业处理软件处理遥感数字图像后,新生成的图像异常亮点过多,对比度过强,这些都影响到遥感数字图像原始信息的提取,最终影响到地质填图的实施和可信度。目前,所采用的各种遥感数字图像对比度增强和彩色合成增强方法,都存在不能有效解决像素点亮度值经过增强后损失的问题。如何将遥感数字图像中含有的原始数据信息完整无损的提取出来,正是我们要考虑和解决的问题。这直接关系到主成分分析、小波变换等后续工作的顺利展开,从而为地质填图打下坚实的基础。本研究以无损平移双向对比度拉伸算法为理论基础,尝试提出一种尽量减少像素点亮度值丢失的改进算法,为遥感数字图像处理后续工作的展开提供坚实基础。采用遥感数字图像处理技术直接进行地质填图是世界性难题,我们选取浙江省东部沿海区域中生代酸性侵入岩为研究对象,首次尝试利用遥感数字图像处理技术进行直接地质填图。
[Abstract]:Geological mapping refers to the process of defining, describing and exploring the geological age, strata, structure and mineral resources of a particular area. The selection of its scale can be selected according to the actual situation, and the most commonly used is 1: 500-1: 50000. During the field exploration of some areas (such as Himalayan Mountains in China) in the traditional geological work, there will be blind exploration areas due to the influence of such factors as the harsh geographical environment and the bad climate in these areas. In the traditional geological mapping method, geological workers usually select special geological sites for mapping. For example, when mapping on a scale of 1: 200000, one geological spot is selected for observation every two square kilometers, and there are blind areas. There is no guarantee of the accuracy of the mapping. Filling a 1: 200000 geological map manually requires two years of work by a geological unit (200-300 people), which is costly. Digital geological mapping, with remote sensing digital images as a means of comprehensive and detailed observation of the whole region without blind area, is conducive to the geological staff to have a macroscopic understanding and grasp of the whole geological mapping area in time and space. The geological mapping results are closer to the objective reality. In recent years, with the development of remote sensing digital image processing technology in geological mapping, geologists are increasingly aware of its importance and irreplaceable. At present, remote sensing digital image is transformed by correlation processing method as the reference of traditional geological mapping. There are many problems in geological mapping using remote sensing digital image processing technology. For example, in the process of remote sensing digital image preprocessing, there are some problems, such as loss of pixel brightness, blue color of color composite image and unsuitable contrast, which is not conducive to visual interpretation, which leads to image distortion. The effects of different image acquisition devices on the effective pixels in the images are consistent. For example, for images of different bands, all effective pixels are strong if they are strong, and all effective pixels are weak if they are weak. After processing remote sensing digital image by commercial processing software, the newly generated image has too many bright spots and strong contrast, which affects the extraction of original information of remote sensing digital image, and finally affects the implementation and credibility of geological mapping. At present, all kinds of remote sensing digital image contrast enhancement and color combination enhancement methods can not effectively solve the loss of pixel brightness value after enhancement. How to extract the original data information from remote sensing digital image is the problem that we should consider and solve. This is directly related to the smooth development of principal component analysis (PCA) and wavelet transform (WT), thus laying a solid foundation for geological mapping. Based on the theory of lossless translation bidirectional contrast stretching algorithm, an improved algorithm is proposed to minimize the loss of pixel brightness value, which provides a solid foundation for the following work of remote sensing digital image processing. It is a worldwide problem to use remote sensing digital image processing technology to directly map geology. We choose Mesozoic acid intrusive rocks in the eastern coastal area of Zhejiang Province as the research object. It is the first time to use remote sensing digital image processing technology for direct geological mapping.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P623.6;TP751

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