Image continuity at different levels of zoom for fringe patterns

Fringe patterns are raw output data from many measurement systems including laser interferometers and moiré systems. For instruments with a range of zoom levels to measure the object at different scales, a technique (algorithm) is needed to combine and/or compare data to obtain information at different levels of details. A technique to keep the continuity of output images both at different levels of zoom and within the same level of zoom is developed and demonstrated. Image registration is used to correlate images, find relative zoom values, and obtain shift between images in the lateral plane. Fringe patterns from a moiré system and a laser interferometer are used as images to be stitched and demonstrate the technique. Interferomteric fringes are used to find the required parameters to inter-relate locations and scale of the fringe patterns at different levels of zoom. The calculated parameters are scale and translation in both directions; these parameters make it possible to locate the coordinates of the region that the measurement system is zoomed in on, related to the area with lower magnification and relative locations of images within the same level of zoom. Results show that this technique is capable of finding the scale and shift parameters within the resolution of one pixel and therefore can restore continuity between images at different levels of zoom.