Method and program product for determining a radiance field in an optical environment

• US 20050046828A1
• Filed: 08/25/2004
• Published: 03/03/2005
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: University of South Florida (State University System of Florida)
• Original Assignee: University of South Florida (State University System of Florida)
• Inventors: Reinersman, Phillip N., Carder, Kendall L.
• Granted Patent: US 7,286,214 B2
• Time in Patent Office: Days
• US Class Current: 356/214
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

A hybrid method is presented by which Monte Carlo techniques are combined with iterative relaxation techniques to solve the Radiative Transfer Equation in arbitrary one-, two- or three-dimensional optical environments. The optical environments are first divided into contiguous regions, or elements, with Monte Carlo techniques then being employed to determine the optical response function of each type of element. The elements are combined, and the iterative relaxation techniques are used to determine simultaneously the radiance field on the boundary and throughout the interior of the modeled environment. This hybrid model is capable of providing estimates of the under-water light field needed to expedite inspection of ship hulls and port facilities. It is also capable of providing estimates of the subaerial light field for structured, absorbing or non-absorbing environments such as shadows of mountain ranges within and without absorption spectral bands such as water vapor or CO₂ bands.

Claims

1. A method of determining a radiance field in an optical environment, said method comprising the steps of:

generating a model of the optical environment;

partitioning the modeled, optical environment into discreet, contiguous regions; and

applying Monte Carlo techniques to determine an optical response function for each region for which the optical response function cannot be analytically defined.

2. A method as set forth in claim 1 further comprising the step of combining the optical response function for each region.

3. A method as set forth in claim 2 wherein the step of combining the optical response function for each region comprises utilizing an output of one region as an input to a contiguous region.

4. A method as set forth in claim 2 further comprising the step of applying iterative relaxation techniques to determine the radiance field on a boundary and throughout the modeled, optical environment.

5. A method as set forth in claim 1 wherein the step of applying Monte Carlo techniques to each region comprises solving the Radiative Transfer Equation (RTE) for each region to obtain an end solution.

6. A method as set forth in claim 5 further comprising the step of calibrating data from an optical sensor in response to the end solution.

7. A method as set forth in claim 6 wherein the step of calibrating data comprises adjusting gain of the optical sensor in response to the end solution.

8. A method as set forth in claim 6 wherein the optical sensor is located on at least one of a remotely operated vehicle (ROV), an autonomous underwater vehicle (AUV), a piloted aircraft, an autonomous aircraft, a semi-autonomous aircraft, a piloted spacecraft, an autonomous spacecraft, and a semi-autonomous spacecraft.

9. A method as set forth in claim 5 further comprising the step of validating data from an optical sensor in response to the end solution.

10. A method as set forth in claim 9 wherein the optical sensor is located on at least one of a remotely operated vehicle (ROV), an autonomous underwater vehicle (AUV), a piloted aircraft, an autonomous aircraft, a semi-autonomous aircraft, a piloted spacecraft, an autonomous spacecraft, and a semi-autonomous spacecraft.

11. A method as set forth in claim 5 further comprising the step of determining an optical sensor to deploy in response to the end solution.

12. A method as set forth in claim 5 further comprising the step of adjusting an optical sensor in response to the end solution prior to deployment of the optical sensor.

13. A method as set forth in claim 1 wherein the optical environment is underwater.

14. A method as set forth in claim 1 wherein the optical environment is subaerial.

15. A program product for determining a radiance field in an optical environment wherein program product code is stored on computer readable media and comprises:

a modeling code for generating a model of the optical environment;

a partitioning code for partitioning the modeled, optical environment into discreet, contiguous regions; and

an application code for applying Monte Carlo techniques to determine an optical response function for each region for which the optical response function cannot be analytically defined.

16. A program product as set forth in claim 15 further comprising a combination code for combining the optical response function for each region.

17. A program product as set forth in claim 16 further comprising a relaxation code for applying iterative relaxation techniques to determine the radiance field on a boundary and throughout the modeled, optical environment.