Jenkin, M. R. M. and Jepson, A. D., Recovering local surface structure through local phase difference measurements, CVGIP: IU, 59: 72-93, 1994.
Previous work has demonstrated that the task of recovering local disparity measurements can be reduced to measuring the local phase difference between bandpass signals extracted from the left and righ images. These earlier techniques were presented as the first simple stages of a more complex stereopsis algorithm. Various local phase difference measurement techniques are examined and a new technique based upon normalized crosscorrelation is presented. A more complete stereopsis algorithm based upon this technique capable of recovering local surface structure from raw image measurements is described. Results obtained with the algorithm are shown on random dot stereopairs, standard stereopairs from the xisting literature, and on a calibrated stereopair for which the ground truth is known.
Jenkin, M. R. M. and Jepson, A., Detecting floor anomalies, Proc. British Machine Vision Conference, 731-740, 1994.
When a robot moves about a 2D world such as a planar surface, it is important that obstacles to the robot's motions be detected. This classical problem of "obstacle detection' has proven to be difficult. Many researchers have formulated this problem as being the process of determining where a robot cannot move due to the presence of obstacles. An alternative approach presented here is to determine where an robot can go by indentifying floor regions for which the planar floor assumption can be verified. A stereo vision system is developed for Floor Anomaly Detection (FAD), and its relationship to existing stereo obstacle detection algorithms is described.
Robinson, M. and Jenkin, M., Reative low level control of the ARK, Proc. Vision Interface 94, pg. 41-47, 1994.
This paper describes the design and implementation of a robot guidance system which integrates a classical occupancy grid based global path planner to construct a global plan and a low-level subsumption based architecture to safely execute it. The global path planner generates a correct path from the robots current state to a goal state according to a static map of the world, and the low-level architecture is given the task of avoiding any unexpected or unmodelled obstacles. By dividing the task of driving the robot to a mapped goal into a classical AI task and a reactive subsumption one, the ARK robot takes advantage of the best of both technologies. Results obtained using a RWI B12 mobile base, an onboard reactive control system and the ARK global path planner are shown.
Jenkin, M. R. M. and Tsotsos, J. K., Active stereo vision and cyclotorsion, Proc. IEEE CVPR 94, pp. 806-811, 1994.
When a particular point is fixated by an active stereo system different portions of the world are brought into interocular alignment. This region is known as the horoptor. Through an examination of the horoptor under different viewing conditions it is demonstrated that for certain binocular tasks it is desirable to manipulate the horoptor by rotating (torquing) the cameras about their optical axes. This manipulation can be passive for operations such as stereo based obstacle detection for mobile robots, or active for active binocular heads. Techniques for both situations are presented.
