NON-CONTACT DISTORTION MEASURING DEVICE AND NON-CONTACT DISTORTION MEASURING METHOD

PROBLEM TO BE SOLVED: To provide a non-contact distortion measuring device and a non-contact distortion measuring method that secure a sufficient measurement range from an elastic deformation area to a plastic deformation area for one imaging part, and can highly accurately measure distortion at least in the elastic deformation area.SOLUTION: According to the present invention, in image data of a test piece 2 captured by an imaging part 3, two reference points Mand Min an imaging visual field 6 of the imaging part 3 are used as calculation data to calculate a predetermined physical quantity about distortion of the test piece 2. When at least one of two reference points Mand Mused as the calculation data arrives at a predetermined setting area or a value based on positions of areas of the two reference points arrives at a predetermined setting value, a reference point 23 to be used as the calculation data is switched over to two reference points Mand Mpresent in the imaging visual field 6 and the predetermined physical quantity is calculated from these switched-over two reference points Mand M.