Computer Holographic Measurement of Machine Parts by Laser Interferometry

(1)为测量机械零件物面偏差，研制了一种新型干涉仪，该干涉仪采用CCD图像传感器代替原样机中的全息图像。CCD图像传感器的引入使测量更加稳定。(2)将各干涉条纹图对参考面和物镜面的亮度数据转换为不连续相位差。本报告还提出了将计算机全息技术应用于数据处理的建议。该技术能有效地串联相。(3) CCD图像传感器上的干涉条纹图案涉及到较厚的条纹密度，同时也包含相当数量的噪声。对于相邻条纹之间的图案连接等有待解决的问题，即使采用上述技术加以缓解，也仍然存在。针对这一问题，在实验中介绍了在参考光束路径中插入凹透镜减少条纹、利用目标表面形状和采用两种不同波长光束源的外差法等方法。这些方法成功地处理了从亮度数据到形状偏差的数据。(4)从干涉条纹图的亮度数据计算相位差时，相移法应该取多少干涉条纹图并不明确。通过一些平面试件的一系列试验，可以确定6-8张样板就足够了。这一结果大大提高了数据处理的效率。

(1) To measure a deviation of objective surface of machine parts, a new interferometer by using the CCD image sensor instead of hologram in the previous proto-type interferometer was developed. The Introduction of the CCD image sensor gives stable measurement.(2) The brightness data of each interference fringe pattern to reference and objective surfaces is converted to discontinuous phase difference. Also a proposal in this report, that is, the computer holographic technique, was applied to the data processing. The technique enable phase to concatenate efficiently.(3) The interference fringe pattern on the CCD image sensor involves a thick density of fringes, and it also contains a considerable amount of noise. The problem to be solved such as pattern connected between neighboring fringes is remained, even if it is relieved by the technique mentioned above. For this problem, some methods by reducing the fringes by inserting concave lens in the path of the reference beam, by applying target surface form and by the heterodyne method using two beam sources with different wave lengths were introduced in the experiment. These methods were successful for data processing from the brightness data to the form deviation.(4) It is not distinct how many interference fringe patterns should be taken by phase shifting method to calculate phase difference from brightness data of interference fringe pattern. From a series of experiment using some plane test pieces, it is cleared that 6-8 sheets of the pattern are sufficient. This result increases considerably efficiency of data processing.