OF OCEANIC ENGINEERING 1 Curved Shape Reconstruction Using Multiple Hypothesis Tracking

| Panoramic sweeps produced by a scanning range sensor often defy interpretation using conventional line of sight models, particularly when the environment contains curved, specularly re ective surfaces. Combining multiple scans from di erent vantage points provides geometric constraints necessary to solve this problem, but not without introducing new di culties. Existing multiple scan implementations, for the most part, ignore the data correspondence issue. The multiple hypothesis tracking (MHT) algorithm explicitly deals with data correspondence. Given canonical observations extracted from raw scans, the MHT applies multiple behavior models to explain their evolution from one scan to the next. This technique identi es di erent topological features in the world to which it assigns the corresponding measurements. We apply the algorithm to real sonar scans generated speci cally for this investigation. The experiments consist of interrogating a variety of two dimensional prismatic objects, standing on end in a 1.2 m deep fresh water tank, from multiple vantage points using a 1.25 MHz pro ling sonar system. The results re ect the validity of the algorithm under the initial assumptions and its gradual performance degradation when these assumptions fail to characterize the environment adequately. We close with recommendations that detail extending the approach to handle more natural underwater settings. Keywords| Data association, multitarget tracking, shape reconstruction, sonar.