结合分形特征及边缘信息的不变角点提取算法

A new algorithm combined fractal signature and edge  information for invariant corner extraction

  • 摘要: 角点特征在图像配准、目标识别等方面有着重要的应用,如何稳定的提取出对图像的几何变换和灰度变化都具有不变性的角点是研究的热点问题。直接利用灰度分布信息提取的角点稳定性较好,但定位精度不高,而利用边缘信息提取的角点定位精度高,且对几何变换具有较强的不变性,但稳定性较差。若有机组合两者,有可能提取各方面性能都比较优越的角点。为此,我们设计了一种结合分形特征和边缘信息的角点提取算法,分三步执行:首先,提取图像中满足要求的边缘,并进行编组;然后,计算各边缘点属性及相应的显著性值;最后,利用局部非最大值抑制,提取出满足要求的角点。实验表明,本文的角点提取算法对图像的几何变换和灰度变化都具有较好的不变性,且计算效率高。

     

    Abstract: Corner is a very important feature in the fields of image registration and target recognition. And it is a hot issue how to extract corners that are invariant to geometry transform and intensity change. Algorithms that use intensity directly to extract corners are robust, but poor in localization. Algorithms that use the information of edges to extract corners are outstanding in localization and invariant to geometry transform, but poor in robustness. If making use of these two kinds of information, an algorithm may extract corners with good property in every aspect. So we design an algorithm for corners extraction combining edge information and fractal signature. The algorithm is divided into three steps: firstly, extract edges of image and organize into groups. Secondly, compute the properties and distinct values of every point on the edge. Finally, extract satisfactory corners using nonmaximal suppress. The experiments show that the proposed algorithm for corner extraction can deal with the case of rotation and zoom of the image, and has good property in localization.

     

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