초록 ▼

In connection with a method of interpreting thermographic data for nondestructive evaluation of subsurface structural irregularities in a sample object, the sample object is thermally excited and then allowed to cool. As the thermal energy level on the object\s surface changes, a series of positiona

In connection with a method of interpreting thermographic data for nondestructive evaluation of subsurface structural irregularities in a sample object, the sample object is thermally excited and then allowed to cool. As the thermal energy level on the object\s surface changes, a series of positionally-fixed infrared images of the object are acquired. The method calculates a pixel sum set for each image in the series by counting the number of pixels in each image which display each of the different pixel shades of gray (or colors). The mathematical moments of each of the functions derived from the pixel sum sets are then calculated, producing a single total energy value for each image, the total energy values collectively being referred to as a total energy value set. The total energy value set acquired from the sample object is compared to a control total energy value set expected from an infinitely thick, perfectly homogenous object to identify anomalous surface infrared radiation patterns, indicating subsurface structural irregularities in the sample object. Alternatively, instead of taking the mathematical moment of the pixel sum sets, the pixel sum sets themselves may be compared individually to a control pixel sum set expected from an infinitely thick, perfectly homogenous object, likewise identifying anomalous surface infrared radiation patterns.

대표청구항 ▼

A method of nondestructive evaluation of subsurface structural properties of an object, comprising the steps of: irradiating a surface of said object thereby creating an irradiated surface to which thermal energy is imparted to said object; acquiring a series of positionally fixed 2-dimensional ther

A method of nondestructive evaluation of subsurface structural properties of an object, comprising the steps of: irradiating a surface of said object thereby creating an irradiated surface to which thermal energy is imparted to said object; acquiring a series of positionally fixed 2-dimensional thermal images from an emissive surface of said object, wherein successive said images are acquired at successive times during a fixed time period as the level of thermal energy present on said emissive surface changes, each said image having a plurality of pixels, each said pixel corresponding to a unique position on said emissive surface, wherein each said pixel is associated with a corresponding finite index value which is related to a measurement of a thermal energy level associated with said pixel\s corresponding position on said emissive surface; summing, for each possible said index value of each individual said image, the number of said pixels associated with each said possible index value of said image, establishing for each image a pixel sum set; and determining, with reference to said pixel sum sets, which of said images was acquired at a time when said emissive surface exhibited an anomalous infrared radiation pattern.