Stereo Vision Guided By Fringe Projection Signals

With the development of science and technology,three-dimensional measurement technology plays an increasingly important role in many fields such as industrial production,biomedicine,driverless,surveying and mapping.In recent decades,domestic and foreign scholars have proposed many methods of 3D measurement.Binocular stereo vision is one of the most widely used methods.The binocular stereo vision three-dimensional measurement technology based on structured light is a research hotspot in recent years due to its high flexibility,high measurement accuracy and fast processing speed.The stereo matching technique based on fringe projection signal is one of the most widely used ones.However,in order to ensure the matching accuracy and reduce the amount of matching calculation,it is necessary to attach a physical label or the like to the surface of the object to be reconstructed as a guide,and this often causes inconvenience or difficulty in actual use.In order to overcome the inconvenience of sticking physical labels on the surface of objects,this thesis first proposes a stereo matching technique based on the relative phase of sinusoidal projection fringes.In order to improve the matching and 3D reconstruction accuracy,this paper proposes a class of binocular stereo matching guide by the absolute phase map of fringe projection signals.In the binocular stereo matching method with wrapped phase guidance,the experimental system consists of two cameras at the same horizontal plane and a projector located between them.The three-frame phase-shifted horizontal sinusoidal fringe image is projected by the projector,and the phase measurement profilometry is used for fringe analysis to obtain the wrapped phase.In this method,the stereo matching cost is composed of the SAD matching and the wrapped phase difference between the left and right matching points cost of different weights,and the phase difference as a threshold defines the matching region to traverse all the pixels on the image to obtain a matching disparity map,which is used for the 3D reconstruction.The method uses the wrapped phase feature as the matching constraint and the weighted matching cost,which avoids the use of physical tags.The experimental results show that the method can obtain more accurate matching results.The stereo matching method guided by the absolute phase employs the absolute phase values corresponding to one-to-one in the left and right angle images as the matching basis,which is possible to effectively improve the accuracy of the wrapped phase based stereo matching.To this end,this paper uses two-frequency and three-frequency fringe phase unwrapping techniques to obtain the absolute phase of the fringe signal and use absolute phase to guide the matching.Since the three-frequency fringe phase unwrapping method is robust to noise,the recovered absolute phase is more reliable,so the accuracy of the stereo matching is higher,thus the 3D reconstruction result is more accurate.The experimental results prove the effectiveness of the proposed method.