3D Vision and Radiological Sensor Fusion

Nuclear material trafficking is a threat to national security, and being able to detect and track people carrying nuclear material is vital to protecting our country’s interests and our people. However, inexpensive radiation detectors have limitations: they are isotropic, unable to detect the direction of the incident radiation; and they are additive, unable to detect a difference between multiple sources of radiation. These limitations leave the inexpensive radiation detectors unfit for many security applications. We explore new ways to enhance the functionality of these inexpensive radiation detectors by fusing them with various 3D vision sensors. We have developed new methods of simultaneous vision-radiation sensor calibration, single source localization and tracking, multi-source localization and tracking, and tracking a source behind visual occlusions.

3DV 2017 3DV 2015
Tracking Radioactive Sources through Sensor Fusion of Omnidirectional LIDAR and Isotropic Rad-detectors Low-Cost Depth and Radiological Sensor Fusion to Detect Moving Sources
Kristofer Henderson, Kelsey Stadnikia, Allan Martin, Andreas Enqvist, Sanjeev J. Koppal Phillip Riley, Andreas Enqvist, Sanjeev J. Koppal
Tracking radioactive sources in large spaces has applications for homeland security, airport and port surveillance as well as military and security uses. Unfortunately, source localizing radiological detectors are extremely expensive, and those with low prices are isotropic – i.e. they integrate radiation from a sphere of directions centered at the sensor. In this paper, we show that omnidirectional depth sensors and isotropic radiological detectors have complementary strengths and can enable many applications. We model the source strength of radiological sources and integrate these with LIDAR measurements and a Kalman filter tracker. This enables applications such as tracking behind walls and detecting multiple radiological sources in the same scene. Radiological sensors are depth sensors. However, unlike a conventional depth sensor, they sense the proximity of only radioactive portions of the scene. Tracking such sources in 3D can impact homeland security, airport and port surveillance and the military. Unfortunately, the radiological sensors with the highest SNR, the fastest ready time and the lowest prices are unidirectional – i.e. they integrate all radiation from a sphere of directions centered at the sensor. We combine such devices with commercial depth sensors to break this directional ambiguity. We first survey and introduce radiological sensing as a interesting application area for the 3D vision community. Next, we propose a joint calibration algorithm for 3D sensors and unidirectional, or single cell, radiological sensors. Finally, we show applications for tracking people carrying radiological sources.
Paper (3DV 2017) Paper (3DV 2015)
Proximity-based Sensor Fusion of Depth Cameras and Isotropic Rad-detectors
Kristofer Henderson, Xiaomeng Liu, Kelsey Stadnikia, Allan Martin, Andreas Enqvist, Sanjeev J. Koppal
Video result of using a motion graph with the blind tracking algorithm from the paper “Proximity-based Sensor Fusion of Depth Cameras and Isotropic Rad-detectors” to visualize the motion of a radiological source carrier behind a visual occlusion with automatically synthesized human motion.
Radiation Measurement Dates
Paper (TNS 2020)