摘要
航空影像中,窗户纹理的合理描述对建筑物提取具有重要意义。依据灰度图像中窗户区域呈现出的明暗变化规律,在建筑物垂直边缘检测的基础上,利用时频分析和Radon变换描述了窗户纹理的周期性和方向性。实验结果表明,合理地描述窗户纹理可用于获取较高层建筑物存在的确凿证据、其垂直边缘的准确位置以及局部墙面水平方向,其为建筑物检测和三维信息的获取提供了一条新的有利途径。
In aerial images, a good description for window textures is of great significance for building extraction. In this paper, based on the result of vertical line extraction, the time-frequency analysis and the Radon transform are used to describe the directivity and periodicity of widow texture. First, in order to acquire periodic texture signals, gray-levels down the vertical lines are picked-up; and in order to enhance signal's robustness for noise and to catch the transversal orientation of texture, gray-levels along several quantitative directions are accumulated based on vertical lines, just like the well-known Radon transform. Second, the Fourier spectrum analysis is adopted to deduce the existence of window texture and its transversal orientation (namely the horizontal orientation of wall). With this understanding, the reliability of corresponding vertical line is ensured. However, its actual pixel positions are needed to be verified furthermore. To do so, the short-time Fourier spectrum of texture signal is computed sequentially, and the part with the same periodicity indicates the accurate location of vertical line. Lastly, the experimental results demonstrate that, reasonable analyses of window texture can be used to acquire reliable evidences for the presence of buildings and exact locations of their vertical lines, and to calculate local horizontal orientations of walls. The proposed algorithm provides a new favourable approach for the detection and acquisition of 3D information of buildings.
出处
《中国图象图形学报（A辑）》
CSCD
北大核心
2004年第10期1175-1181,共7页
Journal of Image and Graphics
基金
国家自然基金项目(60172066)
国家863计划项目(2001AA136070)
