Visual measurement of a 3-D plane pose by a cylindrical structured light

A simple and reliable method for measuring the depth and orientation of a local area of an object surface is proposed. The prototype system consists of a camera, a He-Ne laser, and a beam expander for producing a cylindrical beam. The cylindrical beam is actively projected onto the surface of the object, and the distortion of the light pattern is fitted into ellipse. Without computation of 3-D range data, the depth and orientation of object surface are directly determined by ellipse parameters. In a noisy environment, this method reliably offers 3-D information even if the light pattern is partially missing. The measurement error and its source are discussed and experimental results are shown. Due to its simplicity and reliability, this method may be implemented for various robotic tasks requiring 3-D information on the relationship of the robot´s end effector to its task environment