针对现有点衍射三维坐标测量系统中的坐标高精度解调问题，提出了一种基于Levenbery-Marquardt (L-M)算法的点衍射干涉测量方法。基于L-M算法的点衍射测量技术是以点衍射干涉理论为基础，在实现干涉场相位分布信息解调的基础上运用基于L-M算法的二重迭代算法重构出点衍射源的三维坐标。为验证所提出测量方法的可行性，同时进行了计算机仿真和测量实验，并与三坐标测量机的测量结果进行了对比。结果表明：该测量方法可在xyz三维方向上100 mm×100 mm×300 mm空间范围内实现优于微米量级的测量精度。该测量方法具有不依赖算法迭代初值、测量精度高、运算速度快、抗噪声能力强等诸多优点，在三维坐标测量及测量系统的校准中具有较好的实用性。

Aiming at the precise demodulation of three-dimensional coordinate with point-diffraction interferometer, a method based on Levenbery-Marquardt (L-M) algorithm is proposed for three-dimensional coordinate measurement. With the phase distribution demodulated in point-diffraction interferometry, a double-iterative method based on L-M algorithm is applied to reconstruct the three-dimensional coordinate of point-diffraction source. Both computer simulation and experimental measurement comparing with coordinate measurement machine are carried out to verify the feasibility of the proposed measurement method. Experimental results show that the proposed method can both reach the measurement precision in the order of micron within a 100 mm×100 mm×300 mm working volume. This measurement method does not rely on the initial iteration value, and also has high measurement precision, fast processing speed and preferable anti-noise ability. It is of great practicality for measurement of three-dimensional coordinate and calibration of measurement system.