A General Approach for Extracting Affine Invariant Regions
Yi Su · Dianzi xuebao · 2008
Using scale-space theory and the local shape of auto-correlation matrix,a new general approach is proposed to extract affine invariant regions.First,the feature points and their characteristic scales are detected by the local maxima of normal Gaussian derivatives over scale-space;Then,the auto-correlation matrices,which are used to describe local image structure,are computed on the characteristic scales of feature points.The extracted ellipse regions are affine invariant.Four affine invariant region algorithms,namely Harris3D,Laplace3D,Hessian3D and Localjet43D,are presented using the general approach.The experimental results show the four algorithms are invariant to illumination,rotation and scale changes.The affine invariance is verified by the simulation test we designed for affine invariance.Comparing the four algorithms,we find that the performance of other three algorithms is similar except for Harris3D.