Shape from refocus

Abstract

We present a method exploiting computational refocusing capabilities of a light-field camera in order to obtain 3D shape information. We consider a light-field constructed from the relative motion between a camera and observed objects, i.e. points on the object surface are imaged under different angles along the direction of themotion trajectory. Computationally refocused images are handled by a shape-from-focus algorithm. A linear sharpness measure is shown to be computational advantageous as computational refocusing to a specific depth and sharpness assessment of each refocused image can be reordered. We also present a view matching method which further stabilizes the suggested procedure when fused with sharpness assessment. Results for real-world objects from an inspection task are presented. Comparison to ground-truth data showed average depth errors on the order of magnitude of 1 mm for a depth range of 1 cm.