An electronic shearography system can measure deformation of an object and/or test the object for defects. Two laterally sheared images of the same object are produced by reflecting coherent light from the object, and directing rays, originating from different points on the object, into an image sensor. The rays become collinear, or nearly so, before entering the image sensor, where they produce a recordable interference pattern having a relatively low spatial frequency. The shearing effect comes from two mirrors, positioned to reflect light from the object. One mirror is partially reflective and the other mirror is totally reflective. The mirrors are arranged such that two laterally sheared images are formed, and the arrangement eliminates the need for further optical elements in performing the shearing. Thus, the invention simplifies the optical system, and increases its efficiency. The system can be used to measure relative displacements of two points on the same object, or of two points on different objects. The system can also be used to detect leaks in packages, by detecting changes in the interference pattern caused by changes in refractive index due to gas leaking from the test object.