Efficient object localization with variation-normalized Gaussianized vectors

Effective object localization relies on efficient and effective searching method, and robust image representation and learning method. Recently, the Gaussianized vector representation has been shown effective in several computer vision applications, such as facial age estimation, image scene categorization and video event recognition. However, all these tasks are classification and regression problems based on the whole images. It is not yet explored how this representation can be efficiently applied in the object localization, which reveals the locations and sizes of the objects. In this work, we present an efficient object localization approach for the Gaussianized vector representation, following a branch-and-bound search scheme introduced by Lampert et al. [5]. In particular, we design a quality bound for rectangle sets characterized by the Gaussianized vector representation for fast hierarchical search. This bound can be obtained for any rectangle set in the image, with little extra computational cost, in addition to calculating the Gaussianized vector representation for the whole image. Further, we propose incorporating a normalization approach that suppresses the variation within the object class and the background class. Experiments on a multi-scale car dataset show that the proposed object localization approach based on the Gaussianized vector representation outperforms previous work using the histogram-of-keywords representation. The within-class variation normalization approach further boosts the performance. This chapter is an extended version of our paper at the 1st International Workshop on Interactive Multimedia for Consumer Electronics at ACM Multimedia 2009 [16].