基于高速LED阵列的条纹结构光三维测量方法

Three-Dimensional Measurement System of Fringe-Structured Light Based on High-Speed LED Array

针对数字光处理(DLP)投影仪投影速度低从而限制结构光三维测量速度的问题,采用具有兆赫兹量级切换速度的LED阵列作为投影光源,提出一种基于高速LED阵列的条纹结构光三维测量方法。具体地,使用高速LED阵列投影二值条纹图案,通过对投影系统的镜头进行轻微离焦从而在被测三维物体表面获得正弦条纹,然后结合相移法和多频外差法对物体三维高度进行解算重建。使用所提实验系统在21000 frame/s的投影速度下对旋转速度为3000 r/min的阶梯物体进行三维测量,系统对动态物体的测量速度达到6000 Hz,测量精度达到0.1 mm,实现了对高速运动物体的三维形貌重建,同时展现出高速LED阵列作为投影光源提升三维测量速度至兆赫兹量级的可行性。

Projection speed of a digital light processing projector is low,which limits the three-dimensional(3D)measurement speed of structured light.To solve this problem,a 3D measurement system of fringe-structured light based on a high-speed light emitting diode(LED)array is proposed using the LED array with terahertz switching speed as the projection light source.Particularly,the high-speed LED array is used to project a binary fringe pattern,and a sinusoidal fringe is obtained on a measured 3D object's surface by slightly defocusing the lens of the projection system,and the object's height is calculated.Afterward,the object is reconstructed by combining phase-shifting and multifrequency heterodyne methods.As an experiment,the proposed system was used for 3D measurement of a stepped object with a rotation speed of 3000 r/min at a projection speed of 21000 frame/s.The proposed system can measure a dynamic object at a speed of 6000 Hz,and the measurement accuracy reaches 0.1 mm,which realizes 3D shape reconstruction of highspeed moving objects.In addition,it shows the feasibility of using a high-speed LED array as a projection light source to improve 3D measurement speed to megahertz.