Screen-Camera Calibration Using Gray Codes

In this paper we present a method for efficient calibration of a screen-camera setup, in which the camera is not directly facing the screen. A spherical mirror is used to make the screen visible to the camera. Using Gray code illumination patterns, we can uniquely identify the reflection of each screen pixel on the imaged spherical mirror. This allows us to compute a large set of 2D-3D correspondences, using only two sphere locations. Compared to previous work, this means we require less manual interventions, combined with a more robust screen pixel detection scheme. This results in a consistent improvement in accuracy, which we illustrate with experiments on both synthetic and real data.