Stereo time-of-flight

This paper describes a novel method to acquire depth images using a pair of ToF (Time of Flight) cameras. As opposed to approaches that filter, calibrate or do 3D reconstructions posterior to the image acquisition, we propose to combine the measurements of the two cameras at the acquisition level. To do so, we define a three-stages procedure, during which we actively modify the infrared lighting of the scene: first, the two cameras emit an infrared signal one after the other (stages 1 and 2), and then, simultaneously (stage 3). Assuming the scene is static during the three stages, we gather the depth measurements obtained with both cameras and define a cost function to optimize the two depth images. A quantitative evaluation of the performance of the proposed method for different objects and stereo configurations is provided based on a simulation of the ToF cameras. Results on real images are also presented. Both in simulation and real images the stereo-ToF acquisition produces more accurate depth measurements.