Retina-like visual sensor for fast tracking and navigation robots

This paper describes the development of an anthropomorphic visual sensor which generates a spatially variant resolution image by using a retina-like structure. This sensor consists of a dove prism for image rotation and two linear CCD sensors with 512 pixel/line resolution and holds approximately 45 kbytes of image data. The retina-like sensor has variable resolution with increasing density towards the center of the visual field and yields a polar-coordinate image directly. The motion analysis of the object in the scene from the optical flow is considerably simplified if the velocity is represented in polar coordinates, compared to the case when the image is represented in cartesian coordinates. A calibration procedure for the proposed retina-like sensor is also presented with experimental data to verify the validity of the system. Development of this sensor holds promise in applications to high-speed tracking systems, such as the eyes of navigation robots, because it has data reduction and polar mapping characteristics.