Research On Non-contact Three-dimensional Surface Measurement

With more than three decades of development,the non-contact three-dimensional shape measurement technology has a wide range of applications in many fields,such as industrial testing,quality control,marine prospecting,medical measurement,virtual reality,etc.Under the impetus of this huge application requirements,optical three-dimensional measurement technology as an important branch of the non-contact three-dimensional shape measurement technology is used more widely,but because the differences in shape and size of detecting object,to maximize the balance of detecting methods' ease of use and accuracy becomes more important.Due to the fast development of Charge Coupled Device array camera and digital projection technology,Phase Measurement Profilometry gets more attention base on its broad application and high accuracy.Among these,dual-frequency grating method has drawn many attentions because of its simplicity in optical path and principle,low requirement of equipment,higher accuracy and level of automation comparing with other methods.In this paper,we first state the basic classification and development of three-dimensional shape measurement and then analyze the advantages and disadvantages of various detection techniques.We investigate the projected grating method and phase analysis techniques in depth.To ensure the accuracy of detection,the correction of grate period and calibration of coordinate system and parameter is researched.On this basis,in order to further avoid the error,dual-frequency projected grating method and the phase unwrapping method is given,which is theoretically analyzed the characteristics and advantages of this approach.Finally,non-contact topography detection system is established based on the dual-frequency projected grating method and the phase unwrapping method.We study its accuracy and ease of use.With this detection system,we finish the three-dimensional shape measurement and three-dimensional reconstruction of a aircraft model,indicating that it has a certain practicality.