I have got many feature points after the Hessian-Affine feature point detection.now,how can I do the Region Selection?do you have any similar codes with you?

Many feature points and characteristic regions are obtained after the Hessian Affine feature detection. However, some of the feature points are useless and redundant because of the weakness of a region and the overlap between the regions. At first, the region selection removes over large or small regions, because a big or small characteristic region will be vulnerable if the local geometric transform is applied. In our experiments the regions whose characteristic scale is below 2 or above 12 are removed. Moreover, the region with smaller second derivative test discriminant is also removed when there are regions overlapped with each other. An image has been divided into two parts after the region selection, the selected characteristic regions and the remainder regions.