| Because of the unique reflective properties different from diffuse reflective surface,bright surface is widely used in all walks of life.Iterative product updates are accompanied by stricter processing and more accurate measurement requirements.In some cases,the surface accuracy of a bright surface will greatly affect its performance,but it is difficult to measure this by ordinary three-dimensional morphology measurement methods.In order to ensure product quality and further improve production efficiency,it is important to study the fast and accurate three-dimensional morphology measurement technology for the bright plane.A scheme based on binocular vision combined with phase deflection to measure the three-dimensional morphology of bright surface is proposed.Binocular system layout uses the lateral placement of camera.The complete LCD display-binocular camera-adjustable stage measurement system is integrated in a customized framework.The main research contents include:1.Research on phase unwrapping technology.The absolute phase of sinusoidal stripes is solved by four-step phase shift projection and frequency doubling.Reverse phase error compensation is performed within the principal phase diagram to complete the correction of the non-linear phase error in the phase shift method to improve the unwrapping accuracy.2.Research on system calibration technology.The whole measurement system calibration is divided into binocular system calibration and screen position calibration.Binocular camera calibration is based on custom checkerboard target.Screen position calibration is done by first calibrating the screen image,then combining the law of mirror reflection to get the relative position relationship between the camera system and the real screen.The position parameters obtained by the system calibration are optimized using the Levenberg-Marquardt algorithm to reduce the calibration error.3.Research on morphology reconstruction algorithm.Combining the uniqueness of the normal vectors on the bright surface with the polar constraints of the camera,the efficiency of matching point search is improved,and the smoothness constraints on the mirror are applied to improve the accuracy of matching point search.The traditional triangulation method is improved to find spatial points,and the accuracy of surface points to be measured is improved.4.Using the completed system to measure the three-dimensional morphology of the standard plane mirror and the rear-view mirror,and to analyze the accuracy of their respective surface recovery,good reconstruction results can be obtained.In addition,the standard measurement block is used to measure the three-dimensional morphology of a standard plane mirror at two locations 17 mm apart in space.The measured distance is 16.909 mm,and the relative error is 0.535%.The experimental results verify that the proposed scheme has high measurement accuracy and stability. |
