3-D Volumetric Gamma-ray Imaging and Source Localization with a Mobile Robot
This addresses the need for efficient radiation detection and localization in fields like nuclear safety or security, representing an incremental improvement by combining existing technologies.
The paper tackles the problem of localizing multiple gamma-ray sources in cluttered environments by integrating a Compton gamma camera with a mobile robot to create 3D radiation maps, achieving an average localization accuracy of 0.2 m in laboratory tests.
Radiation detection has largely been a manual inspection process with point sensors such as Geiger-Muller counters and scintillation spectrometers to date. While their observations of source proximity prove useful, they lack the directional information necessary for efficient source localization and characterization in cluttered environments with multiple radiation sources. The recent commercialization of Compton gamma cameras provides directional information to the broader radiation detection community for the first time. This paper presents the integration of a Compton gamma camera with a self-localizing ground robot for accurate 3D radiation mapping. Using the position and orientation of the robot, radiation images from the gamma camera are accumulated over a traversed path in a shared frame of reference to construct a consistent voxel grid-based radiation map. The peaks of the map at pre-specified energy windows are selected as the source location estimates, which are compared to the ground truth source locations. The proposed approach localizes multiple sources to within an average of 0.2 m in two 5 x 4 m^2 and 14 x 6 m^2 laboratory environments.