1. A method for testing the deformation of test objects with diffuse scattering surface that are subjected to different stresses, for which method the object surface is tested section-by-section with an interferometric measuring head with camera that uses an interferometric technique for measuring an area, the areas of displacement or expansion on the object surface, caused by different stresses, are detected in the test object images on the image sensor of the camera, the images created on the image sensor are fed to an image processing system for the further processing, the displacement or the stress/expansion condition of the test object is computed from the generated images by the image processing system, characterized in that the optical ray path of the camera for the interferometric measuring head is determined through a calibration. the camera for the interferometric measuring head is moved with a defined relative movement to the test object from one section of the object surface to the next, light sections are generated on the interferometrically measured sections of the test object surface, the generated light sections on the object surface are detected with the aid of a camera, the spatial coordinates of the light sections are computed with a triangulation computation, the spatial coordinates of the surface sections are determined from the spatial coordinates of the light sections and the appropriate spatial coordinates are assigned to the interferometrically detected deformation data with the aid of the obtained spatial coordinates for the surface sections and the data for the relative movements performed by the interferometric measuring head.