A NEW METHOD FOR IMAGE SEPARATION OF OVERLAPPED IMAGES FROM A 2-LAYERED PRINTED-CIRCUIT BOARD (PCB)

Conventional laminography provides cross-sectional X-ray imaging which separates the top and bottom sides, or any other layer of the printed circuit board (PCB), into separated images. However, only an image on the focal plane is obtained by a set of projections. Furthermore, the image is blurred by superimpositions of the out-of-focus structures. This paper presents a new method for image separation via object trans lation with a moving X-Y table instead of synchronously rotating err t ranslating two components, i.e. a source and detector. This method use s a recursive process with a simple mathematical function which is der ived analytically by the X-ray projection geometry. An X-ray imaging s ystem has been constructed for the purpose of evaluating the proposed method, and was used for the test sample experiments. The experimental results confirm that the method is a powerful tool for separating obj ects from overlapped X-ray images. (C) 1997 Elsevier Science B.V.