仿射协变的G-质心

AFFINE COVARIANCE OF G-CENTROID

图像质心保持仿射协变,但仅可用于消除平移。为方便地提取仿射不变特征,需构造保持仿射协变且异于质心的类质心点。现有算法要么计算量大,要么对二值图像不适用。针对这种情况,提出G-质心,通过改造在极坐标系中图像质心的定义得到,引入极径方向积分的变换函数,使得目前大多的类质心构造算法均是其特例。实验结果表明,通过引入中心投影类的变换函数,所得G-质心可比广义质心、交叉权重质心等算法具有更优的抗噪性能。

Centroid of the image keeps affine covariance,but it can be only used to eliminate translation.In order to extract affine invariant features conveniently,it is necessary to construct centroid-like points that keep affine covariance and are different from the centroid.The existing algorithms are either computationally expensive or not suitable for binary images.In view of this,G-centroid is proposed.It was obtained by modifying the definition of centroid in the polar coordinate system,and the transformation function of integral along radial direction was introduced,thus making most of current centroid-like construction algorithms are special cases of the proposed G-centroid.Experimental results show that obtained G-centroid is more robustness to noise by introducing functions about central projection,compared with the generalized centroid,cross-weighted centroid and other methods.