In order to improve tiny displacement measurement accuracy of heterodyne interferometer, based on its principle several error sources which affect measurement accuracy, such as non-linear error, strip high exponential terms, stabilization of laser and phase fractionization, were analyzed. The heterodyne interference was sampled by a super high speed camera named PhantomV12. 1. The gray level distribution of the sampling image was calculated.1 From the cyclic variation its correlation coefficient, the displacement and its measurement accuracy were obtained. The results indicate that sampling frame speed is directly proportional to displacement distinguishing ability and enhancing sampling frame speed can diminish the effect of variable velocity and sampling error on the accuracy. Test data indicate that measurement precision improves distinctively when the frame speed is below 1000FPS,with finy uniform velocity,and decreases when the kinematic velocity grows up.%为提高微位移测量精度,在外差干涉测量原理基础上分析了非线性误差、激光稳频性及位相细分度等误差源.利用PhantomV12.1超高速数字摄像机对外差干涉采样,从采样图像灰度分布相关系数的周期性变化测量位移及其精度.结果表明:采样帧速与外差干涉位移分辨率成正比,高帧速采样能够降低变速运动及采样误差对测量精度的影响.在匀速微动条件下帧速低于1000FPS时精度提升显著,误差随被测物运动速度增加而变大.
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