# Face recognition on on tilted images

From what I learned, viola jones needs images with faces upfront. Tilting the head a few degrees to each side can botch the algorithm. Is it possible to take an image, take a several rotated copies of it and run the algorithm on each one?

This limitation sounds like only a minor neusense to me. Is there a stronger reason for the limitation?

• What exactly do you mean by tilted? Where did you read that? A few degrees? Are you sure? – D.W. Mar 12 '18 at 19:31
• Tilted - move the head to the sides. To make the task more manageable, Viola–Jones requires full view frontal upright faces - Wikipedia on Viola-Jones. Not sure how many degrees would qualify as not "frontal upright", but I ask why any rotation of the head should have an affect? – CIsForCookies Mar 12 '18 at 19:50
• I couldn't find any place in the Wikipedia article that says that tilting the head a few degrees to each side causes errors. Where are you getting that from? Are you sure? That is not my understanding. I suspect you are starting from a faulty premise. – D.W. Mar 12 '18 at 21:21
• The requirement of an upright frontal face does not disqualify tilted head? I thought that was the exact meaning of this – CIsForCookies Mar 13 '18 at 5:03
• That's not what you wrote. Again, you wrote "Tilting the head a few degrees to each side can botch the algorithm". I'm adding some highlighting there to focus your attention to a specific part that I've tried to draw attention to twice. I don't see any support for that statement in Wikipedia. – D.W. Mar 13 '18 at 5:18