介绍了拉伸视频引伸计、数字图像相关（DIC）技术等光测方案的技术原理，以及其在虚标实测、局域化强塑性能分析、拉伸应变痕（吕德斯效应）的直接观测等领域的实际应用。此外，通过分析传统电子式宽度引伸计在塑性应变比r值测试方面的技术缺陷，提出了通过跟踪试样宽度轮廓变化，或通过二维DIC技术定义多对初始宽向标距，利用宽度变化的均值计算r值，可提高r值测试的可重复性与可靠性。

The technical principles of video extensometer and digital image correlation (DIC) technology were introduced, with the applications including the real strain measurement upon the virtual gauges, the analysis of the local strength and plasticity, the direct characterization of the strain trace (Luders effect). Moreover in comparison with the drawbacks of plastic strain ratio r value measurement by regular electric transversal extensometer, a new optical measurement solution to determine the r value with high reproducibility and reliability was proposed, by employing the averaged transversal strain to calculate r value, and through monitoring the width change of specimen contour or the real measurement upon several pairs of virtual initial transversal gauges by two-dimensional DIC technology.