Yu Tsung-Chih, Shan Hsu, Pham Thi Thu Hien, Lo Yu-Lung
Department of Mechanical Engineering, National Cheng Kung University, University Road, Tainan 701, Taiwan.
Appl Opt. 2009 Aug 10;48(23):4568-76. doi: 10.1364/ao.48.004568.
A method is proposed for obtaining full-range sequential measurements of the slow axis angle and phase retardation of linear birefringent materials (LBMs) using a full-field heterodyne interferometer with a charge-coupled device (CCD) camera and an image processing algorithm based on a three-frame integrating-bucket method. The dynamic ranges of the principal axis and phase retardation measurements extend from 0 degrees to 180 degrees and from 0 degrees to 360 degrees , respectively. The proposed method not only enables full-range measurements of the slow axis angle to be obtained, but also allows a decision to be made as to whether the principal axis labeled by the manufacturer is the slow axis or the fast axis. The standard deviations of the slow axis angle and phase retardation measurements are found to be 0.14 degrees and 0.27 degrees, respectively. In addition, it is shown that the noises induced by environmental disturbances are reduced by elimination of the dc component of the output light intensity in the image processing algorithm. We also investigate the sensitivity of the measured error caused by the orientation of LBM.
提出了一种使用带电荷耦合器件（CCD）相机的全场外差干涉仪和基于三帧积分桶法的图像处理算法，来获取线性双折射材料（LBM）慢轴角度和相位延迟的全范围顺序测量值的方法。主轴和相位延迟测量的动态范围分别从0度扩展到180度和从0度扩展到360度。所提出的方法不仅能够获得慢轴角度的全范围测量值，还能确定制造商标记的主轴是慢轴还是快轴。慢轴角度和相位延迟测量的标准偏差分别为0.14度和0.27度。此外，结果表明，通过在图像处理算法中消除输出光强的直流分量，可以降低环境干扰引起的噪声。我们还研究了LBM取向引起的测量误差的灵敏度。
