Blurred photos can not only be rescued but used to create a sharper, higher-resolution image than if it was taken perfectly sharp.
As a photographer, there is nothing worse than looking back at an image and realizing it is all blurry. But new research reveals that there could be precious data in that soft photo.
A new paper from Brown University demonstrates that blurry photos can ultimately create a sharper, higher-resolution image than if the picture were perfectly sharp.
“We all know that when you shake a camera, you get a blurry picture,” says Pedro Felzenszwalb, a professor of engineering and computer science at Brown, in a press release. “But what we show is that an image captured by a moving camera actually contains additional information that we can use to increase image resolution.”
Getting More Resolution from a Blurry Image
Camera sensors are made from an array of pixels. When light hits the sensor, the sensitive pixels convert that energy into an electronic signal, which becomes the photo.
The photo’s dimensions are constrained by how many pixels are in the sensor. For example, a 6,000 x 4,000 array of pixels equals a 24-megapixel sensor.
But that’s when a sharp photo is taken; when the camera moves during an exposure and the shot is blurred, the light spills across more than one pixel. Brown University has developed an algorithm that pinpoints where those fine details were supposed to be and uses it to increase the resolution of the image beyond the normal capability of the sensor.
It is a little like focus stacking or HDR bracketing, except that the motion blur provides extra information from just a single exposure, rather than multiple.
“There was some prior theoretical work that suggested this shouldn’t be possible,” adds Felzenszwalb. “But we show that there were a few assumptions in those earlier theories that turned out not to be true. And so this is a proof of concept that we really can recover more information by using motion.”
There are intriguing use cases for such a technology, including restoring historic photos that suffered from bad motion blur to a sharp image, and it could also be helpful to photographers who shoot from moving aircraft. Smartphone camera manufacturers may also be interested.
“There are existing systems that cameras use to take motion blur out of photos,” Felzenszwalb says. “But no one has tried to use that to actually increase resolution. We show that’s something you could definitely do.”
The research was published in arXiv.