散斑是激光三角传感器测量不确定度极限的根本影响因素。提出了一种用于旋转对称激光三角传感器的激光散斑的仿真方法,获得了仿真散斑图像。在旋转对称的三角传感器中,投射的激光点在检测器上被成像为一个环,从而散斑也相应是圆弧形。研究了散斑的特性,该散斑在环的半径方向上服从主观散斑的特性,其尺寸由光学系统的数值孔径决定。而在环的切线方向上,其本质上是客观散斑,由于光学系统存在折返光路,其尺寸由物体到检测器的光程、投射的激光光斑尺寸和成像圆环的半径决定。实验结果表明,仿真结果与散斑理论一致。基于仿真给出了对旋转对称三角传感器位移测量不确定度极限的分析,结果表明,使用旋转对称形式的传感器光学布局,在相同的光学系统数值孔径和使用同样的灰度质心算法的情况下,可达到传统激光三角测量不确定度的1/5。Speckle is the fundamental uncertainty factor in laser triangulation.A method to simulate the speckle in rotationally symmetric triangulation was presented and the simulated image was obtained.In this kind of triangulation sensors,the incident laser point will be imaged to a ring on the detector and the speckle is accordingly arc shaped.Properties of this kind of speckle were studied.The speckle size in radius direction of the ring obeyed the subjective speckle,and is determined by the number aperture of the optical system.In tangent direction of the ring,the speckle is essentially an objective speckle,its size is determined by the optical path length from the object to the detector,the area of the incident laser spot,as well as the radius of the imaged ring because of optical path was folded.Experiments showed that the simulation result was coincident with speckle theory.Based on the simulation,an analysis of the uncertainty limits of rotationally symmetric triangulation sensor was given.It shows that using the optical layout in our sensor,an uncertainty about 1/5 of traditional triangulation was estimated with same optical system numerical aperture and grey centroid algorithm.国家自然基金国际合作项目(60416312);; 国家自然基金项目(60375011,60575028);; 安徽省自然基金项目(04042044);; 2006年度中德合作PPP项目;; 新世纪优秀人才支持计划资助项目(NCET-04-0560
