Synthetic reference thermal imaging method
First Claim
1. In an infrared (IR) transient thermography system wherein a sequence of image frames is acquired from an IR sensitive camera, each sequentially acquired image frame comprising an array of pixels and having assigned a frame number that corresponds to elapsed time, a method of analyzing thermal imaging data-frames wherein a synthetically generated temperature-time reference curve is used to determine pixel contrast versus time data.
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Abstract
In an infrared (IR) transient thermography system a sequence of image frames is acquired from an IR sensitive focal-plane array camera. Each sequentially acquired image frame is made up of an array of pixels and has assigned a frame number that corresponds to elapsed time. A method of analyzing thermal imaging data-frames is presented wherein a synthetically generated temperature-time reference curve is used to determine pixel contrast-versus-time data.
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Citations
12 Claims
- 1. In an infrared (IR) transient thermography system wherein a sequence of image frames is acquired from an IR sensitive camera, each sequentially acquired image frame comprising an array of pixels and having assigned a frame number that corresponds to elapsed time, a method of analyzing thermal imaging data-frames wherein a synthetically generated temperature-time reference curve is used to determine pixel contrast versus time data.
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3. In an infrared (IR) transient thermography system wherein a sequence of image frames is acquired from an IR sensitive focal-plane array camera, each sequentially acquired image frame comprising an array of pixels and having assigned a frame number that corresponds to elapsed time, a method for determining contrast versus time data for a pixel, comprising the steps of:
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(a) acquiring pixel IR intensity versus time data corresponding to a selected analysis pixel in an IR image of an object from a plurality of image frames; and
(b) subtracting from said pixel intensity data a synthetic temperature time reference standard, Ts(t), computed according to the following mathematical relationship;
- View Dependent Claims (4, 5, 6)
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7. A method for determining a thickness of an object having a surface which can be visualized as an array of pixels, comprising the steps of:
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(a) rapidly heating the surface of an object;
(b) recording pixel intensity in a sequence of IR images, each image having an assigned sequential frame number related to time elapsed since heating the object surface in step (a);
(c) determining pixel contrast data based at least upon pixel intensity and a temperature-time reference standard, Ts(t), computed according to the following mathematical relationship;
- View Dependent Claims (8, 9)
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10. An infrared (IR) transient thermography method for determining a thickness of an object, comprising the steps of:
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a) using an IR sensitive focal-plane array camera to acquire pixel intensity data from a sequence of IR image frames of the object, each image frame comprising a plurality of pixels and having an assigned sequential frame number related to time elapsed since heating the object surface;
b) calculating a temperature versus time data standard, Ts(t), from a mathematical thermal reference model representative of one-dimensional heat flow into a semi-infinite medium;
c) determining pixel contrast data by subtracting said temperature versus time data standard from acquired pixel intensity data to develop temperature-time contrast data for at least one pixel; and
d) determining actual thickness at a resolution element of the object corresponding to the pixel using said contrast data, said determination based on a heat-flow invariant relationship between an inflection point in the contrast data and a heat-flow characteristic time dependent upon thermal diffusivity of the object. - View Dependent Claims (11, 12)
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12. The method of claim 10 wherein the object is rapidly heated using a flash lamp device.
Specification