Spatio-Temporal Defect Pixel Interpolation using 3-D Frequency Selective Extrapolation

Flat panel X-ray detectors allow the immediate availability of the acquired images for display. However, they provide images with defective areas amongst others due to manufacturing problems. In this contribution, we present a frequency selective extrapolation method in order to restore these defects by extending the surrounding signal into the defective area. In case of static radiographs, the spatial surrounding is evaluated by a 2-D approach. Defects in sequences acquired by cine-angiography or fluoroscopy are processed by 3-D extrapolation. The defects are replaced by extrapolating the signal from the spatial and at the same time temporal surrounding, taking previous and subsequent frames into account. Hence, inherent motion compensation is accomplished. The application of the spatial and where applicable spatio-temporal extrapolation approach allows to restore smooth areas, edges, patterns as well as noise. The ability to restore noise is especially important for medical images because it leads to a natural appearance of the concealed defective areas.