基于TM影像的草原沙漠化信息增强方法的研究

分别选择浑善达克沙地西部、中部和腹地3个区域，利用遥感影像的假彩色合成、比值增强、归一化植被指数（NDVD、掩膜技术等遥感图像增强处理技术，对3个区域进行遥感数字图像处理，探讨增强草原沙漠化信息的有效方法。研究发现：NDVI图像中，不同级别的草原沙漠化在灰阶上易于区分，尤其是轻度沙漠化和重度沙漠化，反差非常大；TM3／TM4比值运算增强了沙漠化信息，特别是半固定沙地的信息，再与原图像中的TM4和TM5进行假彩色合成，形成含有比值运算信息的合成图像，更加突出了草原中度沙漠化的信息。

Study on Methods of Enhancing Grassland Desertification Information Based on TM Data

In order to find the methods of enhancing grassland desertification information, the west, the middle and the center regions in Hunshandake sand of Inner Mongolia were chose. Using the remote sensing image processing technologies based on TM data, such as false color synthesis, ratio processing, NDVI, and mask technology, the effective ways of enhancing the grassland desertification information were explored. It is found that the NDVI image could separate the lightly desertification well from the serious desertification. TM3/TM4 images strengthened the desertification information, especially the information of moderate desertification. Then, combining it with TM4 and TM5 of the original images, the false color-synthesis is carried on to form the composite images, which contained the information of ratio operation, and thus to emphasize the moderate desertification information of the grassland.