Dr. Shree Nayar, Director of Columbia University’s Computer Vision Lab, studies the science behind photography. “Wouldn’t it be nice if we had cameras we can wrap around things?” he wondered one day.
So his team went and made one.
Researchers at the lab — including research engineer Daniel Sims and postdoctoral researcher Yonghao Yue — explored this question with their Flexible Sheet Camera study. The team made a flexible lens array that can wrap around everyday objects, capturing unique images and mounting in ways never possible before.
Nayar, one of the study leaders, put this project in the perspective of our current limitations. “Cameras today capture the world from essentially a single point in space,” he said in a release. “We are exploring a radically different approach to imaging.”
The problem with flexing a lens is that it produces gaps in the image. “Imagine you have a sheet and you have lots of pixels on the sheet, and you have little lenses that are attached to each pixel,” Nayar told Digital Trends. “Now you have the directions in which you are looking, and when you bend it, the directions just fan out. When they do fan out, it’s very easy to see that you’re going to miss information between the pixels; there are going to be gaps.”
The initial thought was to attach a little lens to individual pixels. But Nayar pointed out that this would never work. “When you have millions of pixels, that would be impossible to control.” This lens avoids that problem by using the native properties of the material.
The camera lens looks vaguely like a flexible solar tile. When bent, it captures an image that may appear altered but is still a high quality full picture. The team used silicone for the prototype sheet camera that lets the focal length of each lens vary with the curvature of the sheet, meaning there is no missing information as the lens deforms.
The key was in the material. Nayar told DT, “if you choose the right materials and the right shape, the material itself deforms in a way that you want, that gives it the right optical properties without adding any additional engineering.” He makes it sound easier that it was, of course. This silicone lens is the result of much testing and experimentation.
To test it, the team positioned a Nikon D90 under a vice that flexed the sheet camera. Photos captured showed that the field of view increased the more it flexed.
“We believe there are numerous applications for cameras that are large in format but very thin and highly flexible,” Nayar said. “The adaptive lens array we have developed is an important step towards making the concept of flexible sheet cameras viable.”
This means that the rubber bumper strip surrounding your car could one day be a 360-degree camera lens. Or that one day, a photographer’s newest dream toy could be a camera the size and shape of a credit card that flexes to adjust the field of view. This study could be the first accurate use of the term “flex-cam.”
Still, we’re a very long way from seeing it on store shelves. Such a system would need to be manufactured relatively inexpensively for broad use, something that will take time and money. This study is simply a step in the right direction. The team will eventually seek a partnership to develop a sensor, but the immediate next step is to share the advancement with the scientific community. The first author of the paper, Daniel Sims will present the prototype at the International Conference on Computational Photography at Northwestern, May 13 to 15.
