Actually ellipses perform pretty well. I've analyzed this a good bit... http://i.imgur.com/82Aksg0.png http://i.imgur.com/82Aksg0.png (lower is better, this sho

Actually ellipses perform pretty well. I've analyzed this a good bit... http://i.imgur.com/82Aksg0.png http://i.imgur.com/82Aksg0.png (lower is better, this shows average score over 100 different input images)