Method and system for high-speed, 3D imaging of optically-invisible radiation

• US 6,815,687 B1
• Filed: 04/14/2000
• Issued: 11/09/2004
• Est. Priority Date: 04/16/1999
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Stojadinovic, Bozidar, Branch-Sullivan, Clair J., McGregor, Douglas S., Kearfott, Kimberlee J.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Harrington, Alicia M.
• Application Number:
  US09/549,464
• Time in Patent Office: 1,670 Days
• Field of Search: 250/330, 250/332, 250/334, 250/392, 250/394, 250/389, 345/8, 353/28, 359/630, 348/115
• US Class Current: 250/389
• CPC Class Codes: H01L 27/14658 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00

Abstract

A high-speed, three-dimensional, gamma-ray imaging method and system as well as a detector and array of such detectors for use therein are provided which characterize radioactivity distributions in nuclear and radioactive waste and materials facilities by superimposing radiation images on a view of the environment using see-through display screens or shields to provide a stereoscopic view of the radiation. The method and system provide real-time visual feedback about the locations and relative strengths of radioactive sources. The method and system dynamically provide continuous updates to the displayed image illustrating changes, such as source movement. A pair of spaced gamma-ray cameras of a detector subsystem function like “gamma eyes”. A pair of CCD cameras may be coupled to the detector subsystem to obtain information about the physical architecture of the environment. A motion tracking subsystem is used to generate information on the user'"'"'s position and head orientation to determine what a user “sees”. The invention exploits the human brain'"'"'s ability to naturally reconstruct a 3D, stereoscopic image from 2D images generated by two “imagers” separated by a known angle(s) without the need for 3D mathematical image reconstruction. The method and system are not only tools for minimizing human exposure to radiation thus assisting in ALARA (As Low As Reasonably Achievable) planning, but also are helpful for identifying contamination in, for example, laboratory or industrial settings. Other optically-invisible radiation such as infrared radiation caused by smoldering fires may also be imaged. Detectors are manufactured or configured in curvilinear geometries (such as hemispheres, spheres, circles, arcs, or other arrangements) to enable sampling of the ionizing radiation field for determination of positional activity (absolute or relative amounts of ionizing radiation) or spectroscopy (energy distributions of photons). More than one detector system may be used to obtain three-dimensional information. The detector systems are specifically suitable for direct visualization of radiation fields.

Claims

1. A method for high-speed, 3D imaging of optically-invisible radiation, the method comprising:

detecting optically-invisible ionizing radiation emitted within an optically-opaque environment to obtain signals using two or more ionizing radiation detectors for converting the ionizing radiation into the signals;

processing the signals to obtain stereoscopic data; and

displaying the stereoscopic data directly to a user'"'"'s eyes in the form of optically-visible radiation images superimposed on a view of the environment so that the user can obtain a stereoscopic 3D view of the radiation by utilizing natural human stereo imaging processes, wherein the stereoscopic 3D view does not interfere with the user'"'"'s view of the environment.

2. The method as claimed in claim 1 wherein the environment is a virtual environment.

3. The method as claimed in claim 1 wherein the environment is an optically-visible environment.

4. The method as claimed in claim 1 further comprising energizing material so that the material emits or deflects the ionizing radiation.

5. A system for high-speed, 3D imaging of optically-invisible radiation, the system comprising:

a detector subsystem for detecting optically-invisible ionizing radiation emitted within an optically-opaque environment to obtain signals using two or more ionizing radiation detectors for converting the ionizing radiation into the signals;

a signal processor for processing the signals to obtain stereoscopic data; and

a display subsystem for displaying the stereoscopic data directly to a user'"'"'s eyes in the form of optically-visible radiation images superimposed on a view of the environment so that the user can obtain a stereoscopic 3D view of the radiation by utilizing natural human stereo imaging processes, wherein the stereoscopic 3D view does not interfere with the user'"'"'s view of the environment.

6. The system as claimed in claim 5 wherein the environment is a virtual environment.

7. The system as claimed in claim 5 wherein the environment is an optically-visible environment.

8. The system as claimed in claim 5 further comprising means for energizing material so that the material emits or deflects the ionizing radiation.

9. The system as claimed in claim 5 wherein the detector subsystem includes a set of field or area detectors.

10. The system as claimed in claim 9 wherein the radiation is gamma-ray radiation and wherein the set of field detectors includes a pair of gamma-ray or other positional radiation detectors.

11. The system as claimed in claim 10 wherein the gamma-ray cameras are scanning gamma-ray cameras and wherein each of the gamma-ray cameras is capable of scanning the environment through a plurality of angles and wherein the signals are processed to locate a source within the environment.

12. The system as claimed in claim 5 wherein the detector subsystem includes a set of point detectors.

13. The system as claimed in claim 12 wherein the signal processor processes the signals to obtain a 3D map of radiation-emitting sources.

14. The system as claimed in claim 5 wherein the detector subsystem includes a set of passive detectors.

15. The system as claimed in claim 5 wherein the detector subsystem includes a set of active detectors.

16. The system as claimed in claim 5 wherein the detector subsystem includes a scintillator and a collimator for directing the ionizing radiation into the scintillator.

17. The system as claimed in claim 16 wherein the scintillator is curved.

18. The system as claimed in claim 5 wherein the detector subsystem includes a compound eye detector.

19. The system as claimed in claim 18 wherein the compound eye detector includes a plurality of individual detectors.

20. The system as claimed in claim 19 wherein the plurality of individual detectors are movable independently or as a group.

21. The system as claimed in claim 18 wherein the compound eye detector includes a single detector movable in three dimensions.

22. The system as claimed in claim 5 wherein the detector subsystem has stereoscopic capabilities.

23. The system as claimed in claim 5 wherein the detector subsystem is portable.

24. The system as claimed in claim 5 wherein the display subsystem includes a see-through display subsystem and wherein the system further includes a tracking system for tracking the display subsystem.

25. The system as claimed in claim 24 wherein the display subsystem is head-mountable.

26. The system as claimed in claim 5 wherein the system provides real-time visual feedback about location and relative strength of at least one radiation-emitting source.