‘Deepfake’ technology can now create completely real-looking human faces
by STEPHEN JOHNSON
- In 2014, researchers introduced a novel approach to generating artificial images through something called a generative adversarial network.
- Nvidia researchers combined that approach with something called style transfer to create AI-generated images of human faces.
- This year, the Department of Defense said it had been developing tools designed to detect so-called ‘deepfake’ videos.
A new paper from researchers at Nvidia shows just how far AI image generation technology has come in the past few years. The results are pretty startling.
Take the image below. Can you tell which faces are real?
Karros et al.
Actually, all of the above images are fake, and they were produced by what the researchers call a style-based generator, which is a modified version of the conventional technology that’s used to automatically generate images. To sum up quickly:
In 2014, a researcher named Ian Goodfellow and his colleagues wrote a paper outlining a new machine learning concept called generative adversarial networks. The idea, in simplified terms, involves pitting two neural networks against each other. One acts as a generator that looks at, say, pictures of dogs and then does its best to create an image of what it thinks a dog looks like. The other network acts as a discriminator that tries to tell fake images from real ones.
At first, the generator might produce some images that don’t look like dogs, so the discriminator shoots them down. But the generator now knows a bit about where it went wrong, so the next image it creates is slightly better. This process continues until, in theory, the generator creates a good image of a dog.
What the Nvidia researchers did was add to their generative adversarial network some principles of style transfer, a technique that involves recomposing one image in the style of another. In style transfer, neural networks look at multiple levels of an image in order to discriminate between the content of the picture and its style, e.g. the smoothness of lines, thickness of brush stroke, etc.
Here are a couple examples of style transfer.