A New Salt Grain-Sized Camera Rivals Others That Are 500,000 Times Larger

With 'crisp, full-color images'.
Irmak Bayrakdar
The new salt grain-sized camera.Princeton University

Witnessing the evolution of the camera has been, and still is, an exciting ride. With new models coming out every year, we've seen the old bulky cameras shrink down to smaller and smaller versions. And while micro cameras are considered as works of art, they're almost always not very talented in composition compared to their professional handheld peers. 

Researchers at Princeton University and the University of Washington disagree; the team announced that they have successfully created an ultra-compact camera that is the size of a coarse salt grain, in a study published in Nature Communications. What's more, the camera can capture clear, full-color images that can compete with conventional camera lens setups that are 500,000 times larger.

A brand new experience from a tiny perspective

What's new? Regular cameras use a series of curved glass or plastics in their lenses to bend the light into focus when taking photographs. The new microcamera the team has created has a new optical system featuring a technology called a metasurface that can be produced like a computer chip, according to a press release by Princeton University.

The metasurface in question is only half a millimeter in size that features 1.6 million cylindrical posts which come in unique shapes and function as an optical antenna. That's where machine learning algorithms come into play. Thanks to machine learning, the posts can produce the highest-quality images and widest views with vibrant colors in a metasurface camera. 

About the production process, Ethan Tseng, a computer science Ph.D. student at Princeton who co-led the study, said “It’s been a challenge to design and configure these little microstructures to do what you want. For this specific task of capturing large field of view RGB images, it was previously unclear how to co-design the millions of nano-structures together with post-processing algorithms.”

Co-lead author Shane Colburn created a computer simulator to automate the testing of different nano-antennas. Because of the number of antennas and the complexity of their interactions with light, this type of simulation can use “massive amounts of memory and time,” said Colburn. He developed a model to efficiently approximate the metasurfaces’ image production capabilities with sufficient accuracy. 

Compared to previous ultra-compact metasurface lens cameras, the new lens easily removes image distortions and limitations to capturing full spectrums of visible light. Usually, tiny cameras work in pure laser light settings of a laboratory or similar ideal conditions to produce high-quality images, but the new camera’s performance in natural lighting is just as better as it is in lab lighting.

The possibilities are endless with micro-cameras. And this new micro-optical system could be used for medical purposes, placed in robots to diagnose and treat diseases and improve imaging for other robots. 

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