Towards flexible sheet cameras: Deformable lens arrays with intrinsic optical adaptation

We propose a framework for developing a new class of imaging systems that are thin and flexible. Such an imaging sheet can be flexed at will and wrapped around everyday objects to capture unconventional fields of view. Our approach is to use a lens array attached to a sheet with a 2D grid of pixels. A major challenge with this type of a system is that its sampling of the scene varies with the curvature of the sheet. To avoid undesirable aliasing effects due to under-sampling in high curvature regions of the sheet, we design a deformable lens array with adaptive optical properties. We show that the material and geometric properties of the lens array can be optimized so that the object-side point spread function corresponding to each pixel widens with the curvature of the sheet at that pixel. This intrinsic adaptation of focal length is passive (without the use of actuators or other control mechanisms), and enables a sheet camera to capture images without aliasing, irrespective of its shape. We have designed a 33×33 lens array, fabricated it using silicone rubber, and conducted several experiments to verify its optical adaptation characteristics. We conclude with a discussion on the advantages of our proposed approach as well as future work.