Wide-Baseline Light Fields Using Ellipsoidal Mirrors

Abstract

Traditional hand-held light field cameras only observe a small fraction of the cone of light emitted by a scene point. As a consequence, the study of interesting angular effects like iridescence are beyond the scope of such cameras. This paper envisions a new design for sensing light fields with wide baselines, so as to sense a significantly larger fraction of the cone of light emitted by scene points. Our system achieves this by imaging the scene, indirectly, through an ellipsoidal mirror. We show that an ellipsoidal mirror maps a wide cone of light from locations near one of its foci to a narrower cone at its other focus; thus, by placing a conventional light field camera at a focus, we can observe a wide-baseline light field from the scene near the other focus. We show via simulations and a lab prototype that wide-baseline light fields excel in the traditional applications involving changes in focus and perspective. Additionally, the larger cone of light that they observe allows the study of iridescence and thin-film interference. Perhaps surprisingly, the larger cone of light allows us to estimate surface normals of scene points by reasoning about their visibility.