为了实现对液态环境中微球三维位置的快速精密测量, 尤其是轴向的测量分辨力和速度, 基于离焦成像测量理论, 结合并改进象限插值法和矢径投影算法, 提出了一种新的方法, 实现了对微球三维方向1 nm测量分辨力的跟踪测量。该方法测量效率高, 对单个粒子轴向位置的测量速率最快达到每秒上百帧甚至更高。进一步讨论了横向位置测量误差对轴向测量分辨力的影响, 分析了轴向方向大范围的跟踪测量分辨力。通过和相同实验条件下的互相关方法对比, 说明该方法在实际测量中具有可行性, 在实现相同轴向测量分辨力的情况下测量效率更高。

To achieve fast and accurate three-dimensional measurements of microspheres in liquid, especially axial tracking resolution and speed, this paper proposes a new measurement method based on off-focus measuring theory and combining quadrant interpolation algorithm and radial projection algorithm. Resolution of 1 nm measurement in 3D directions of microspheres is realized. The method has high measurement efficiency with the fastest measuring rate at individual particle axial position of hundred frames per second and more. The influences of horizontal deviations on axial measurements are further discussed, and axial resolution throughout dozens of micrometers is analyzed. Compared with the cross-correlation method under the same experimental conditions, this measurement method shows feasibility in practical measurement applications and enjoys higher measurement efficiency when achieving the same axial measurement resolution.