RADON-TRANSFORM APPLICATIONS IN OPTICAL INSPECTION

The Radon transform is applied to optical inspection of a piece part on a dark background. It is demonstrated that the Radon transform of a 'test' object in an arbitrary location and orientation can be restored to the same form as the transform of a similar 'reference' object. This can be used to measure the amount of translation and rotation of the object or to introduce rotation and translation invariance properties to calculations performed on transform data. Various image features can be calculated utilizing threshold levels and designated centers to maximize detection capabilities for specific applications. It is shown that it is possible to reconstruct a small region of the image without reconstructing the entire image. This can save time when only a small area is of interest. These techniques for processing Radon transform data are presented in a general manner so that they can be applied to fields other than inspection.