Geometric Calibration of a Time-of-Flight Depth Sensor and a Colour Camera Pair

The joint information provided by the depth sensor and the colour camera has many applications in the field of computer vision. These two imaging devices require preliminary calibration (both intrinsic and extrinsic) to be used for accurate measurements. In this paper, we propose a novel approach to calibrate Intel Creative Senz3D depth sensor that is based on Time-of-Flight (ToF) technology. Since identifying feature points in-depth maps is difficult, we have designed a 2.5D checkerboard pattern with systematically placed holes to be accurately detected from low-resolution depth maps of a ToF camera as well as from high-resolution images of a colour camera. Based on the identified feature points we establish an accurate correspondence between world coordinate and camera coordinate system using the obtained intrinsic and extrinsic parameters of the respective cameras. Evaluation of the proposed method indicates an improvement of 27.13% in average pixel re-projection error with respect to the manufacturer’ s calibration.