Research On Dynamic 3D Imaging Technology Based On Phase Shift Fringe Projection

In the field of industrial production and processing,how to quickly obtain accurate threedimensional shape data plays a vital role in the automation and even intelligence of China’s manufacturing industry.In industrial applications,the optical three-dimensional profile measurement technology based on fringe projection has the most application prospects,with advantages such as non-contact,fast measurement speed,high accuracy,and easy implementation of automated measurement.A challenging proposition is how to restore the three-dimensional appearance of moving objects accurately and quickly.In order to meet this demand in practical applications,this paper proposes a dynamic three-dimensional measurement method,which uses the motion of the object to introduce the fringe phase shift.Through the registration of the object pattern and the calculation of the fringe phase shift value,the multi-step phase shift is used.The technology realizes high-precision and high-resolution reconstruction of three-dimensional information of objects.The main research content and achievements include the following aspects:1.Based on an in-depth understanding of the three-dimensional measurement technology based on projected sine fringe structured light,two projection strategies(single frame and multiframe)based on the technique are discussed,and the key factors that affect the accuracy of these two projection strategies are analyzed.factor.By comparing the commonly used structured light measurement methods of static objects,the intensity distribution model of the projected grating on the surface of the object in dynamic scenes and the phase recovery formula are derived.2.Based on the above theoretical basis,a dynamic three-dimensional measurement method based on sinusoidal fringe projection is proposed.The method is mainly divided into four parts: object pattern registration,inter-frame phase shift estimation,phase recovery,and threedimensional reconstruction.A method of using marker points through template matching is proposed to achieve object phase shift pattern registration.In terms of phase shift estimation,it is proposed to apply the minimum energy method to the estimation of the phase shift value of the large field of view and sinusoidal grating projection.It is verified in theory and simulation that the minimum energy method has higher accuracy in measuring the fringe phase shift and has a stronger Anti-noise ability.Based on the phase shift estimation value of the minimum energy method,it is proposed to use the iterative least square method to recover the phase distribution.This method can not only suppress the impact of random noise between frames,but also does not need to ensure that the phase shift value of each frame is the same.It effectively overcomes the problem that the phase shift is not constant due to the change of the moving speed of the object in the dynamic scene.3.Based on Daheng Vision’s DH-SPOL-CS400 conveyor belt experimental platform,this paper simulates the scenes of pipeline operations in actual industry,builds a dynamic threedimensional measurement system,and performs three-dimensional reconstruction of actual objects.The experimental results verify the feasibility and effectiveness of the measurement method proposed in this paper.