A piezoelectric resonator according to an embodiment of the present invention is a piezoelectric resonator for obtaining a signal of a predetermined resonance frequency from a bulk acoustic wave propagating inside a piezoelectric film. Scalable entropy coding is implemented in accordance with any desired degree of complexity. The opening is spaced apart below the top of the container. The method allows the linearity of counting radiation detectors to be improved, particularly at high radiation intensities, so that the linearity condition for X-ray CT systems is also satisfied. The semi-global edge histogram is based on the horizontally and the vertically grouped image blocks.