Camera calibration and light source estimation from images with shadows
In this paper, we describe how camera parameters and light source orientation can be recovered from two perspective views of a scene given only two vertical lines and their cast shadows. Compared to the traditional calibration methods that involve images of some precisely machined calibration pattern, our method uses new calibration objects: the vertical objects and their parallel shadow lines, which are common in natural environments. In addition to the benefit of increasing accessibility of the calibration objects, the proposed method is also especially useful in cases where only limited information is available. To demonstrate the accuracy and the applications of the proposed algorithm, we present results on both synthetic and real images.