High-speed 3D Measurement System Based On Fringe Projection Profilometry

Fringe projection profilometry,as a 3D measurement technology based on structured light technology,has been widely used in biomedical,cultural relics protection,industrial testing,aerospace and other fields,due to its advantages of high speed,high precision,and non-contact.However,the current 3D measurement system based on fringe projection profilometry is difficult to meet the high-speed measurement requirements of moving objects.Considering that the 3D measurement of moving objects also has a wide range of application.Therefore,the development of a high-speed3 D measurement system has certain scientific significance and application value.The paper starts from the demand analysis of the high-speed 3D measurement system,and studies the hardware selection scheme and the software s ystem architecture.The system uses DLP4500 high-speed projector,BFS-U3-04S2M-CS high-speed camera and Raspberry Pi 4B as the hardware components of the sinusoidal fringe projection module,acquisition module,data processing and control module,and the m obile phone as the terminal controller and displays the 3D reconstruction results.Through the interfaces provided by each hardware,each module is interconnected,and the 3D measurement system is modeled using Sketch Up software.According to the principle s of two-wavelength fringe projection profilometry coding,projector projection and camera capture,the software control and measurement procedures of the system are designed and completed.To realize the control of the Raspberry Pi by the mobile phone,the network communication between the mobile phone and the Raspberry Pi is established through the mobile phone APP.Using the Raspberry Pi,the projector starts to project,triggers the camera to capture synchronously while projecting,and transmit s the captured picture to the Raspberry Pi for data processing.Finally,the result of the 3D reconstruction is displayed on the mobile phone screen.Complete the 3D measurement of the object to be measured.In order to further improve the speed of the 3D measurement system,aiming at the characteristic that the speed of projected binary fringes is much faster than that of sinusoidal fringes,a method of dithering binary fringes by Charles error diffusion is proposed,and the standard sinusoidal fringes are designed to be binarized.The experimental results show that the 3D measurement system designed in this paper has ideal reconstruction results for diffuse objects,complex objects with high surface reflectivity,and moving objects.The phase measurement error is 0.342 rad,the average value is 0.021 rad,and the measurement speed reaches 83 fps.The developed high-speed 3D measurement system based on fringe projection profilometry is expected to be used in intelligent navigation of autonomous driving,human body posture recognition in somatosensory games and other occasions.