Abstract: An input image is inputted into a pre-process circuit and a spatial filter. The pre-process circuit emphasizes a linear shadow or an edge to some extent, or reduces noises overall. Following pre-processing, the image signal is supplied to a direction detection circuit, a direction and its intensity of an area of interest are detected. These two results of the detections are correlated with peripheral areas of interest to some extent by a vector filter. An output of the vector filter is supplied to a spatial filter coefficient generation circuit, and a filter coefficient of the spatial filter is decided. The spatial filter processes the input image based on the direction of the shadow and its intensity, whereby selectively suppressing noise components of the background in real time without damaging the contrasts of a linear shadow or an edge-like shadow.

Abstract: A radiation detector has conversion elements for converting radiation incident from the front side into charges, an electric charge read out elements arranged on the rear side of the conversion elements, the supporting plate of the electric charge read out elements, and a first plate as a main shielding plate arranged on the rear side of the supporting plate. The first plate effectively prevents the leakage radiation or reduces the leakage radiation to the standard value. The first plate, however, generates a large amount of backscattering ray. When the backscattering ray reaches the conversion elements, noise charges are generated to degrade the image quality. A second plate is characteristically inserted between the first plate and the supporting plate. The second plate is designed to have a radiation absorbed dose that is not zero but much littler than that of the first plate.