Hany Farid

So let's go on to our next one, the vanishing points.

If you image parallel lines in the physical world, they will converge to a single point, what's called a vanishing point.

A good intuition for that is the railroad tracks.

Railroad tracks are obviously parallel.

They narrow as they recede away from me and intersect at a single vanishing point.

This is a phenomenon that artists have known for centuries.

But here's the great thing.

AI doesn't know this.

Because AI is fundamentally, as I just described, a statistical process.

It doesn't understand the physical world, the geometry and the physics.

So if we can find physical and geometric anomalies, we can find evidence of manipulation or generation.

Evidence number two.

All right, what else can we learn?

Surprisingly, shadows have a lot in common with vanishing points.

And again, this is a physical phenomena that you expect in natural images, and because AI fundamentally doesn't model the physics and the geometry of the world, it tends to violate these physics.

We now have a very good indication that this image is not authentic.

The most important thing I want you to take away from this is that while it may not be easy, it is possible to distinguish what is real from what is fake.

This image is a bit of a metaphor for how a lot of us feel.

We feel like hostages.

We don't know what to trust anymore.