Advanced Visual Servoing

This chapter builds on the previous one and introduces some advanced visual servo techniques and applications. Section 16.1 introduces a hybrid visual servo method that avoids some of the limitations of the IBVS and PBVS schemes described previously.

Wide-angle cameras such as fisheye lenses and catadioptric cameras have significant advantages for visual servoing. Section 16.2 shows how IBVS can be reformulated for polar rather than Cartesian image-plane coordinates. This is directly relevant to fisheye lenses but also gives improved rotational control when using a perspective camera. The unified imaging model from Sect. 11.4 allows most cameras (perspective, fisheye and catadioptric) to be represented by a spherical projection model, and Sect. 16.3 shows how IBVS can reformulated for spherical coordinates.

The remaining sections present a number of application examples. These illustrate how visual servoing can be used with different types of cameras (perspective and spherical) and different types of robots (arm-type robots, mobile ground robots and flying robots). Section 16.4 considers a 6 degree of freedom robot arm manipulating the camera. Section 16.5 considers a mobile robot moving to a specific pose which could be used for navigating through a doorway or docking. Finally, Sect. 16.6 considers visual servoing of a quadrotor flying robot to hover at fixed pose with respect to a target on the ground.