Digital fringe multiplication of photoelastic images—A new approach

ConclusionsA simple and new approach for digital fringe multiplication of photoelastic image based on the image-division technique is described and demonstrated. By applying the trigonometric identities of different angle relations of cosine function, the fringes can be multiplied to various times. The factor to be multiplied is limited by the resolution of the image-processing system and the quantization errors. The linearity of the system was calibrated effectively using a standard density tablet and the polynomial regression method. This effort makes the following image-division operation more accurate. The use of a PC-based image-processing system eliminates the photographic process and optical equipment of the conventional methods of fringe multiplication.