Method and apparatus for testing objects
First Claim
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.
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Abstract
1. Method and apparatus for testing objects.
2.1 With interferometric test systems, the test object is frequently measured over several sections in order to realize a complete test. If special structural features are found, in particular defects, it is usually difficult to localize the structural features shown on the result images on the object.
2.2 It is the object of the new method to transfer the interferometrically measured data from the various sections to a joint object coordinate system. To achieve this object, the shape of the object is measured and the spatial coordinates for the deformation data on the object surface are determined from this.
2.3 Thus, a method is realized with the invention, which permits determining the exact spatial orientation and position of the discovered structural features on the object. On the one hand, the defects on the object can thus be localized precisely while, on the other hand, an exact quantitative evaluation of the results is possible.
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Citations
34 Claims
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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.
- 20. An apparatus for testing objects (1) with diffuse scattering surface, consisting of an interferometric measuring head (2) with a camera (3) for photographing image data, an image processing system (11) that is connected to the camera (3) and is used to further process the images generated by the camera (3), characterized in that the test system is provided with at least one device (9) for realizing defined relative movements between the interferometric test head (2) and the object surface (1), the test system is provided with a light-section contour detection system (10), comprising at least one device (5, 6) for generating light surfaces (L1, L2), which are oriented toward the camera (4) in such a way that the light sections (P11, P21) created by this device (5, 6) can be observed with the camera (4) on the test object (1), means for determining the spatial coordinates of the light sections, means for determining from this the spatial coordinates for the object surface sections, means for assigning appropriate spatial coordinates to the interferometrically detected deformation data.
Specification