A normal camera uses a lens to bend light so that it hits a sensor. A pinhole camera doesn’t have a lens, but the tiny hole serves the same function. Now two researchers from the University of Utah. have used software to recreate images from scattered unfocused light. The quality isn’t great, but there’s no lens — not even a pinhole — involved. You can see a video, below.
The camera has a sensor on the edge of a piece of a transparent window. The images could resolve .1 line-pairs/mm at a distance of 150 mm and had a depth of field of about 10 mm. This may seem like a solution that needs a problem, but think about the applications where a camera could see through a windshield or a pair of glasses without having a conventional camera in the way.
The only thing special about the window is that all the edges except the one with the sensor have reflective tape applied and the remaining edge is roughed up. The window used was a piece of Plexiglass with three edges heat annealed and the fourth edge sandpapered. The sensor on that fourth edge picks up a seemingly random set of points.
This isn’t the only lensless camera in the works. Caltech, Rice University, Hitachi, Microsoft, and others all have something in mind, although they are generally more obtrusive. The paper discusses some of these and while they do work without lenses, they generally need something more than just a sheet of clear material between you and the scene.
The images aren’t wonderful but, then again, neither were the ones from the first digital camera. They still should be sufficient for many computer vision applications. If you’d rather play with pinholes, they work better than you might think.