BING Objectness proposal estimator linux/mac/windows version implementation, runs at 1000 FPS. More in http://mmcheng.net/bing/ and also http://www.robots.ox.ac.uk/~szheng/DepthProposals.html
If you directly use the data from VOC website, OpenCV has some problems to read them, you might also need to refer to the FAQ at http://mmcheng.net/bing/
I just download http://pascallin.ecs.soton.ac.uk/challenges/VOC/voc2007/VOCtrainval_06-Nov-2007.tar and test one I want to say: this may cause errors