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多光谱遥感亚像元定位的空间引力算法研究

韩文超1,田庆久,陆应诚   

  • 收稿日期:2009-10-29 修回日期:2010-06-17 出版日期:2011-04-25 发布日期:2011-04-25
  • 通讯作者: 韩文超

Spatial Attraction Algorithm for Sub-Pixel Mapping of Multispectral Remote Sensing

  • Received:2009-10-29 Revised:2010-06-17 Online:2011-04-25 Published:2011-04-25

摘要: 针对遥感影像亚像元定位问题,提出一种基于像元空间引力模型的亚像元定位新算法,算法中像元空间引力的表达完全建立在亚像元尺度上,能够有效的表达像元间的空间自相关性;考虑到像元间作用的相互性,亚像元权重的计算将相互吸引的两个相邻像元中地物百分比含量都做为权重参数,强化了空间引力模型;距离函数也合理的表达了像元间的相互作用在距离上的非线性关系。通过迭代运算优化像元间的引力关系,提高像元的空间自相关性。试验结合扬州地区2006年6月份的SPOT假彩色合成影像,在S=5尺度下进行了亚像元制图,获得了水体、植被、水田和城镇四种地物类型的空间结构信息,取得了较好的结果,验证了算法的有效性。

Abstract: Mixed pixels will always be present in remote sensing images, soft classification techniques have been developed to estimate the class composition of mixed pixels, and the accuracy of land cover mapping has been improved, but their output provides no indication of how these classes are distributed spatially in pixels. Sub-pixel mapping is a technique to produce the land cover map at sub-pixel spatial resolution from the land cover proportion images obtained by soft classification methods. In this technique, pixels are divided into sub-pixels, and these fraction values can be assigned to sub-pixels, based on the assumption of spatial dependence. Sub-pixel mapping can represent the land cover class fractions, so it can provide better spatial representation of land cover. A new algorithm is presented for sub-pixel mapping, the algorithm is based on the scale of sub-pixels spatial attraction models, which can express the spatial dependence well. And in this algorithm, taking into account the interaction of pixels between themselves, the proportions of each land cover within two adjacent mixed pixels as the sub-pixel weight parameters will be inputed, which enhanced the spatial attraction model; The distance function is also a reasonable expression of the non-linear relationship at a distance about the interaction among the pixels. Following an initial random allocation of sub-pixels, the algorithm works in a series of iterations, each of which can optimize the attraction relationship among the sub-pixels, by this the algorithm can improve the spatial dependence among the pixels. This algorithm is tested on SPOT image data at S=5 scale factor, and four land covers are mapped, including water, vegetation, paddy field and urban. The result shows that, this algorithm works reasonably well in multiple classes mapping.