​Stuck with a lo-res image? Google's real 'zoom in, enhance' can fix it

Google's neural networks play sketch artist, painting in the blanks of blurry faces to seemingly enhance an image.
Written by Liam Tung, Contributing Writer

Human study: The fractions below the images show how many times a person chose the enhanced image over the real image.

Image: Google

Until now, only Hollywood could zoom and enhance a grainy image to move a plot along with newly clear photographic evidence, but Google's neural network can now do it too. Almost.

Researchers from Google's AI Brain team have devised a pair of neural networks to look at a blurry eight-pixel by eight-pixel image of a face and reconstruct it. While it can't actually recover details that aren't in the original image, it can, like an artist who has prior knowledge of a face, fill in the blanks in a plausible way.

According to Google's researchers, the model they built plays artist by taking details from a real 64-pixel by 64-pixel image, such as a person's hair and face details, to synthesize a 32-pixel image. In this case, the training data was a large number of photos of celebrity faces and bedrooms.

"The conditioning network effectively maps a low-resolution image to a distribution over corresponding high-resolution images, while the prior models high-resolution details to make the outputs look more realistic," Google's Brain researchers explain.

As Ars Technica notes, the conditioning network maps the blurry image with other high-resolution images that, when shrunk to eight by eight, can be used to find a match.

Meanwhile, the prior network has learned that, for example, a brown pixel on the top of the source image is likely to be an eyebrow and so applies hi-res eyebrow-shaped brown pixels to that part of the source.

When human observers were shown the real image of a celebrity face versus the computer enhanced images, 10 percent were fooled. Ars notes that 50 percent would be a perfect score.

Given the enhanced images are impressions of what the network thinks a blurry image would look like, it probably couldn't be used as evidence in a criminal investigation, however it still may help move an inquiry along.

Read more about Google Brain team

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