Weighted Subspace Distance and Its Applications to Object Recognition and Retrieval With Image Sets

We address the problem of measuring the distance between two subspaces, each of which is spanned by an image set. In the existing methods, only the orthonormal basis is used to represent the subspace. However, the images are usually distributed in a limited area, rather than the whole subspace. Therefore, the characteristics of the distribution should also be considered. In this letter, a weighted subspace distance (WSD) is proposed, in which the principal component values of the data set are adopted to calculate the weights. Experimental results on object recognition and retrieval with image sets demonstrate the effectiveness of our proposal.