During low-light conditions, drivers rely mainly on headlights to improve visibility. But in the presence of rain and snow, headlights can paradoxically reduce visibility due to light reflected off of precipitation back towards the driver. Precipitation also scatters light across a wide range of angles that disrupts the vision of drivers in oncoming vehicles. In contrast to recent computer vision methods that digitally remove rain and snow streaks from captured images, we present a system that will directly improve driver visibility by controlling illumination in response to detected precipitation. The motion of precipitation is tracked and only the space around particles is illuminated using fast dynamic control. Using a physics-based simulator, we show how such a system would perform under a variety of weather conditions. We build and evaluate a proof-of-concept system that can avoid water drops generated in the laboratory.

We present a multi-layered display that uses water drops as voxels. Water drops refract most incident light, making them excellent wide-angle lenses. Each 2D layer of our display can exhibit arbitrary visual content, creating a layered-depth (2.5D) display. Our system consists of a single projector-camera system and a set of linear drop generator manifolds that are tightly synchronized and controlled using a computer. Following the principles of fluid mechanics, we are able to accurately generate and control drops so that, at any time instant, no two drops occupy the same projector pixel's line-of-sight. This drop control is combined with an algorithm for space-time division of projector light rays. Our prototype system has up to four layers, with each layer consisting of an row of 50 drops that can be generated at up to 60 Hz. The effective resolution of the display is 50x projector vertical-resolution x number of layers. We show how this water drop display can be used for text, videos, and interactive games.

This paper presents a method to create an illusion of seeing moving objects through occluding surfaces in a video. This illusion is achieved by transferring information from a camera viewing the occluded area. In typical view interpolation approaches for 3D scenes, some form of correspondence across views is required. For occluded areas, establishing direct correspondence is impossible as information is missing in one of the views. Instead, we use a 2D projective invariant to capture information about occluded objects (which may be moving). Since invariants are quantities that do not change across views, a visually compelling rendering of hidden areas is achieved without the need for explicit correspondences. A piece-wise planar model of the scene allows the entire rendering process to take place without any 3D reconstruction, while still producing visual parallax. Because of the simplicity and robustness of the 2D invariant, we are able to transfer both static backgrounds and moving objects in real time. A complete working system has been implemented that runs live at 5Hz. Applications for this technology include the ability to look through corners at tight intersections for automobile safety, concurrent visualization of a surveillance camera network, and monitoring systems for patients/elderly/children.