Inverse perspective transform with manual vanishing point adjustment aided
paper: http://www.ce.unipr.it/people/bertozzi/publications/cr/ieee.ip.gold.pdf
In addition, one can get gamma and theta angle from vanishing point.
Press w/a/s/d to adjust vanishing point manually.
Test using KITTI raw data: http://www.cvlibs.net/datasets/kitti/raw_data.php
