光照鲁棒的非线性相关图像匹配方法
Illumination-Robust Image Matching Based on Non-linear Correlation
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摘要: 在自然场景下的光照变化不可避免,而同一物体在不同光照条件下的成像差异极大,这使得光照变化下的图像匹配成为一个普遍而具有挑战性的问题.为此提出一种对光照变化鲁棒的图像匹配方法,通过设定阈值分割图像来选择比较有区分力的部分像素参与匹配,用2个分量分别描述图像中存在亮度变化的区域和区域内亮度的变化程度.在匹配过程中,以向量之间夹角的大小作为相似度度量,直接利用图像的灰度信息在高维向量空间中考虑图像之间的相似度,克服了在低照度、低信噪比的图像中求边缘、角点、梯度和形状等特征的困难,不受向量模大小(乘性光照变化)以及向量平移(加性光照变化)的影响,即相似度的计算是线性光照不变的.实验结果验证了该方法的有效性.Abstract: Changes in lighting are unavoidable in natural scenes and they have a big effect on the way an object looks, awhich makes it a common challenge to match images taken under different lighting conditions.This paper presents an image matching method which is robust to varying illumination. Discriminative image pixels are extracted by segmenting the original image, awhich are then described by two parts, aone is about the status of region changes and the other is about the change degree in a region.In the matching stage, athe angle of feature vectors is used as the similarity measure in the high dimensional space directly.This similarity measure is invariant to the linear transformation of feature vectors.Compared with SIFT and normalized correlation, athe proposed method needs no primary features such as edges, acorners, agradient or shapes which are very unstable in low contrast and low NSR images.Experimental results demonstrate the validity of our method.
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