"We also investigated hierarchical features where the image is overlaid with a grid of cell size c × c and pixels withins each cell are added up. This is same a

"We also investigated hierarchical features where the image is overlaid with a grid of cell size c × c and pixels withins each cell are added up. This is same as downsampling the image and using the raw pixels in the downsampled image as features." (p. 3) http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-159.pdf http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-15...