Omni-directional vision system with fibre grating device for obstacle detection

In this study, a new omni-directional vision system is presented for localisation and wide field of view (FOV) mapping of the environment. The vision system includes two charge coupled device (CCD) cameras fitted in front of two rectilinear mirrors to sense the environment in a stereo manner. In order to obtain the points representing the obstacles in the environment, a dot-matrix laser pattern created by a fibre grating device (FGD) was used. With the help of the developed mathematical and error estimation models, the distances between the points on the objects and the vision system were determined; and by using synthetic data, the effects of noise on the error rates were analysed. Although the error rates of X-, Y- and Z-axis were increased according to the distance between the obstacle and the vision system for the same horizontal/vertical plane, the errors for X (range) and Z (height) were decreased with the increasing distance between the vision system and horizontal/vertical planes for real world. The main reasons of errors were the size and location of the laser points, reflection errors on the mirrors, sensitivity of the refractive lenses, alignment of the mirror-camera pairs and limitation of the image resolution.