Where to get background sample images for haar training?

This site have some haar negatives from various databases. You can download by svn: svn co http://tutorial-haartraining.googlecode.com/svn/trunk/data/negatives/

UPDATE: It is possible that the repository died, so you can go to GitHub. I found one that was exported automatically from google code here.

you can find it anywhere especially in google.. negative images are just images that does not contain your positive images/samples which is the object of interest.. anything that doesn't contain your object of interest can be a negative samples..