Motion invariant imaging by means of focal sweep

In this paper we evaluate a so-called “sweeping focus camera” of which the camera blur is insensitive to the actual distance to the objects and to the direction and magnitude of the velocities within a scene. This can be achieved by either moving the sensor linearly along the optical axis of the main lens or changing the focal length of the main lens while the shutter is open. A consistently sharp image can then be obtained by the application of a fixed inverse filter kernel, thus preventing the need for depth and motion estimation. Moreover, high frequencies are better preserved during the acquisition, such that the results achieved by inverse filtering are superior to those achievable with conventional shutter/sensor operations.