Patent ID: 8235588

Claim:
A method for automated, contactless and non-destructive testing of a material joint ( 4 ) of at least two mating parts ( 2 , 3 ), a. with the material joint ( 4 ) being a two-section joint which consists of i. a molten zone ( 5 ) and ii. a non-molten zone ( 6 ) surrounding said molten zone ( 5 ); b. with an examination of infrared images taking place in such a way that i. at least one excitation source ( 8 ) excites a test sample (1); ii. at least one infrared sensor ( 9 ) detects a developing heat flow in a sequence of thermal images; iii. result images are obtained from the sequence of thermal images; and iv. the thermal images and the result images are examined; wherein c. the molten zone ( 5 ) is detected from a result image, which illustrates a heat flow dynamics (W) through the material joint ( 4 ), in such a way that i. a minimum threshold value (W min ) is determined which exceeds a heat flow dynamics (W) of an image background (H); ii. a maximum threshold value (W max ) is determined which corresponds to a peak value of the heat flow dynamics (W) through the material joint ( 4 ); iii. a dynamic threshold value (W dyn ) is varied between the minimum threshold value (W min ) and the maximum threshold value (W max ); iv. a sequence of regions (B) of the heat flow dynamics (W) through the material joint ( 4 ) is determined which represent the values of the heat flow dynamics (W) exceeding the dynamic threshold value (W dyn ); v. the regions (B) of the heat flow dynamics (W) are examined with respect to an abrupt change in perimeter (ΔU); vi. the molten zone ( 5 ) is determined as a region (B i ) from the regions (B), the abrupt change in perimeter (ΔU) indicating that a boundary ( 7 ) between the molten zone ( 5 ) and the non-molten zone ( 6 ) is being crossed; and vii. a position and a size of the molten zone ( 5 ) are evaluated.