Stereo videopolarimetry: Measuring and visualizing polarization patterns in three dimensions

Because the human eye is practically blind to the polarization of light, bi ologists dealing with polarization vision of animals, or engineers designin g robots using polarization-sensitive computer vision to enhance contrast i n the optical environment need a technique to image the spatial distributio n of polarized light in the visual environment. Recently, different kinds o f imaging polarimetry were developed to measure the polarization patterns o f objects and natural scenes in a single, two-dimensional, wide field of vi ew. As a further development of this technique, we report here on the reali zation of the addition of depth to scenes imaging the distribution of polar ized light: One kind of stereo videopolarimetry was designed to measure and visualize in three dimensions the polarization patterns in nature and to m imic the ability of animal-eyes to receive visual information from a binocu lar field of view. We demonstrate the power of stereo videopolarimetry on a n applied problem representing (in parallel view stereo format) a three-dim ensional object, a car with a shiny bodywork and also having strong reflect ion polarization. The technical difficulties and hitches of stereo videopol arimetry as well as the importance of the distance of observation, the role of the angle of view, the influence of the color of the object, and the po ssibility to state differences between metallized and non-metallized paints are discussed.