Abstract: A method of detecting cracks in an object includes: capturing a first image of a pattern of marks in a region of interest on a surface of the object; constructing a finite element model of the region of interest having nodes corresponding to the marks in the pattern; subjecting the object to a first mechanical load to produce strains in the object; capturing a second image of the pattern; computing strains in the object based on relative changes in locations of the marks in the first and second images; modifying the finite element model to produce a crack versus surface strain map; capturing a third image of the pattern; and comparing the locations of marks in the third image to the crack versus surface strain map to identify a crack in the object. An apparatus that performs the method is also provided.