为了满足无损检测中复合材料在复杂载荷下多参数变量评估的需求，提出了一种基于光路复用的双功能数字散斑干涉系统，能够同时实现数字散斑干涉和数字剪切散斑干涉测量功能.通过控制其中一个反射镜-波片组合，当该组合离位时，构成数字散斑干涉测量光路，实现离面位移测量；当该组合在位时，构成数字剪切散斑干涉测量光路，实现离面位移空间梯度的测量.测量过程中只需简单切换该组合的位置就可以实现单次加载下被测物体表面离面位移及其空间梯度的同时测量.该系统光路结构简单、切换效率高，能够同时获得高质量的位移及空间梯度测量结果.实验证明，双功能数字散斑干涉系统既具备高抗干扰能力，又具备高灵敏度测试能力，适合复合材料无损检测现场使用.

In order to meet the needs of multi-parameter variable evaluation of composite materials under complex loads in nondestructive testing, a dual-function digital speckle pattern interferometry system based on optical multiplexing is proposed to realize the measurement functions of both digital speckle pattern interferometry and digital shearography. By controlling one of the combinations of a mirror and quarter-wave plate, the optical setup of digital speckle pattern interferometry is formed when the combination is in the first position, allowing the out-of-plane displacement to be measured. The optical setup of digital shearography is formed to realize measurement of slope when the combination is in the second position. During the process of measurement, the out-of-plane displacement and slope of the object surface due to a single load can be simultaneously measured by simply switching the position of the combination. The optical setup of the dual-function digital speckle pattern interferometry enjoys the advantages of simple structure and high switching efficiency. High quality measurement results of displacement and slope can be obtained using the dual-function digital speckle pattern interferometry. It has been proved experimentally that the dual-function digital speckle pattern interferometry is suitable for field use in nondestructive testing of composite materials due to its superior performance in anti-interference and high-sensitivity testing.