光阱中微粒位置高精度检测技术

基于光阱技术的精密传感和测量是光力效应应用由微观精确操控向物理量精确测量的创新和深化，对光阱中微粒位置信息进行高精度测量是实现精密传感和测量的核心；提出了一种采用数字图像处理和曲线拟合相结合进行光阱微粒位置检测的方法，通过数字图像相关方法获得表征微粒位置的归一化自相关函数，并对归一化自相关函数曲线采用最小二乘法进行二次曲线拟合，由此实现亚像素级的微粒位置检测。实验表明，所述方法可以有效抑制硬件量化效应，实现光阱微粒位置的快速高精度检测，相较于直接相关方法，检测精度可至少提升一个数量级，达0.03 pixel。

High precision detection technology of particle positions in optical trap

Precision sensing and measuring based on optical trap technology is innovation and deepening for application of optical force effect from micro-precise manipulation to precise measurement of physical quantities. Precision measurement of position information of the particle in optical trap is key technology of precise sensing and measuring. The method was put forward, which used digital image processing and curve fitting algorithm to detect particle positions in optical trap. The normalized self-correlation function of particle positions was obtained by digital image correlation, and the quadratic curve fitting was used to the normalized self-correlation function curve by least-square method to realize particle position detection of sub-pixel accuracy. Experiments show that the method described in this paper can effectively suppress the quantization effect of hardware and realize fast and high-precision detection of particle position in optical traps. Compared with the direct correlation method, the detection accuracy can be improved by at least one order of magnitude to 0.03 pixel.