Using Phase Shifting Digital Moire To Detect3D Object Shape Differences

With the rapid development of computer technology and modern optical detection technology, optical3D shape detection technology which possesses untouched,high speed, high resolution and low cost advantages has been widely used in quality inspection, computer aided design and medical diagnosis etc..At present, the detection of3D shape mainly focus on individual object, but the research on the differences of two similar objects’shapes is very limited. On the bases of phase shifting moire fringe, digital fringe projection technology, image recognition and translation, and improving moire filtered compositive method, a novel method is proposed to detect the differences of3D shape of objects by using phase shifting digital moire fringe. This method has many advantages, such as easy to operate, fast detection and high accuracy. Especially, the test sample does not need precise reset, which can reduce the detection environmental requirement.Through theoretical analysis and experiments, the main work and results involve:1. By recognizing and translating the image between test sample and standard sample, the test sample and standard sample will be overlap in the image, which accomplish the test sample virtual reset and solve the problem of the real reset.2. Moire filtered compositive method is improved by subtracting the background item from standard sample reference grid and test sample deformation grid respectively, which reduces the difficulty to extract moire fringe, extends its application scope.3. On the basis of test sample virtual reset in the image, a method is proposed by using standard sample reference grid as the reference grid in the phase shifting moire fringe method to realize detecting the differences of3D shape of objects.4. The difference detection system of3D shape of objects is built and related test program is carried out by utilizing MATLAB program. Simulation experiment proves that this method has high measurement accuracy. The feasibility of the method has been verified by experiment.