System and method for remote measurement of displacement and strain fields

An apparatus for measuring full field deformation characteristics of a body, comprising:

• a load tester for deforming a specimen, the specimen having a pattern of optically distinct marks disposed on a planar surface of the specimen;
• camera for acquiring a sequence of images of the pattern of marks before and after deformation of the specimen;
• and a computer processor having programmed instructions thereon for identifying the characteristic points of the mark after eliminating non-marker objects from the sequence of images based on a pixel intensity threshold and an area cut-off criterion, matching the characteristic points between two or more subsequent images, calculating a displacement vector of the characteristic points, and calculating full field displacement and strain based on the displacement vector of the characteristic points;
• and a computer processor having programmed instructions thereon for generating the pattern of optically distinct marks for application to the specimen, said generating including:
• determining a position of a first mark, iteratively determining a position of a next mark with a random number generator having a preset value for mean mark distance, and checking a distance between the next mark and each previous mark to reject the next mark as an overlapping mark if the distance between marks is less than twice the mark radius, and continuing to determine positions for mark until the pattern has a preset minimum number of marks or until a minimum number of iterations has been reached.