Patent ID: 6394646
Filing Date: 2002-05-28
Classification: G01B,G01J,G01N

Abstract:
A high speed infrared (IR) transient thermography method for determining the thickness of an object, comprising the steps of:a) storing pixel intensity data from a predetermined sequence of image frames acquired from an IR sensitive focal-plane array camera, wherein each sequentially acquired image frame is assigned a frame number of increasing value that linearly corresponds to elapsed time; b) determining a pixel contrast curve from the pixel intensity data for a pixel from said sequence of image frames; c) performing Gaussian temporal smoothing of pixel contrast curve data developed in step (b); d) determining a time derivative of the pixel contrast curve data from separate data points in time along the contrast curve after Gaussian temporal smoothing; e) identifying localized peak derivative values in the time derivative of the pixel contrast curve data; f) applying a predetermined weighting function to said localized peak values identified in step (e) to determine a significance value for each derivative peak value identified; g) selecting one contrast curve derivative peak value based on a most significant value determined in step (f); and h) determining an object thickness, L, based on a frame number of an image frame in which the contrast curve derivative peak selected in step (g) occurs.