Calculating virtual focal planes for TDI-imaging

With Today's demands in quality assurance, a thorough inspection of products becomes mandatory for a lot of industrial branches. For example, X-ray scanners replace more and more the simple metal detectors used in food industry. For such scanning applications continuous processing is desirable, because it fits most production processes without the need for further adaptations. To minimize the required X-ray power, a Time, Delay and Integration (TDI) CCD sensor is used to capture the image. While the product moves across the sensor area, the angle of the X-rays changes during the pass. This can be compensated for by adjusting the sensor shift speed to focus on a single plane of the product. If the product has a significant thickness, the image will show artifacts due to the laminographic effect. In this contribution we demonstrate that by the use of inverse filtering images which are focused on planes of different height can be generated out of a single X-ray sensor image.