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Researchers develop an AI that can “relight” portraits post-capture

(Image credit: Yun-Ta Tsai)

If you’ve ever shot an image and then realised too late that the light wasn’t quite right – well, there may be a solution on the way.

Researchers from UC San Diego and Google have unveiled a new neural network they claim to have trained to be able to adjust the lighting in any photo of a human face – change the direction, temperature and quality of the light at will.

The AI was “trained” using a database of images of 18 individuals captured under different directional light sources in a controlled setup, capturing each person from seven different angles using a densely sampled sphere of lights.

As a result, the neural network can replicate these various conditions on new photos – the demonstration video shows various real phone snaps fed into the AI, and the result afterwards that shows the change in their quality of light. It’s clearly early days, but it’s impressive stuff.

The changes in light don’t have to affect the entire image as well – the creators also show how the effect can be applied only to the image’s human subject while leaving the background untouched. 

It works fast too – the creators say that the network can produce a 640 x 640 image in as little as 160 milliseconds, meaning “it may enable interactive user-facing photographic applications in the future.” This presumably means an app could be on the way, and judging by the fact that Google researchers and engineers were involved in the development of the technology, we think we can guess what smartphone range that app might start appearing on (opens in new tab).

Still, all that’s likely a long way off. For now, take a look at the demonstration video (opens in new tab) and see what you think.

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Jon spent years at IPC Media writing features, news, reviews and other photography content for publications such as Amateur Photographer and What Digital Camera in both print and digital form. With his additional experience for outlets like Photomonitor, this makes Jon one of our go-to specialists when it comes to all aspects of photography, from cameras and action cameras to lenses and memory cards, flash diffusers and triggers, batteries and memory cards, selfie sticks and gimbals, and much more besides.  


An NCTJ-qualified journalist, he has also contributed to Shortlist, The Skinny, ThreeWeeks Edinburgh, The Guardian, Trusted Reviews, CreativeBLOQ, and probably quite a few others I’ve forgotten.