Contactless thermography based approach for measuring the rate of corrosion under insulation

A system for determining material loss in a thickness of a structure having a pipe surrounded by an insulator using contactless thermography, the system comprising:

• a thermal camera operable to capture thermal images of the structure, wherein the thermal camera captures a first thermal image at time t0 at which the structure is newly installed, a second image at time tt during operation of the structure and a third image when the pipe is entirely corroded (tinfinity);
• a heating or cooling device positioned near the structure to cause local disturbance in a temperature of the structure operable to heat or cool the structure prior to the capture of each of the first, second and third thermal images;
• one or more processors coupled to the thermal camera and operable to receive the first, second and third thermal images, wherein the one or more processors is configured by code executing therein to:
• determine a first heat flux (Q0) from the first thermal image, a second heat flux (Qt) is from the second thermal image, and a third heat flux (Qinfinity). from the third thermal image;
• determine, to a first order of approximation, a ratio of the metal loss as a ratio of a difference between the first heat flux and the second heat flux to a difference between the first heat flux and the third heat flux (Q0−Qt/Q0−Qinfinity);
• execute a first machine learning algorithm trained using thermal images and historical data to determine a level of corrosion in a metallic pipe structure to determine a corrective coefficient (Cc) based on a detected level of corrosion;
• execute a second machine learning algorithm trained using thermal images and historical data to determine a level of corrosion in a metallic pipe structure to determine a corrective coefficient (Cd) based on a detected level of metallic deposition;
• and
• determine a corrected metal loss by applying the corrective coefficients (Cc, Cd) to the ratio of the metal loss to arrive at a final metal loss estimate.