IMAGE PROCESSING PROGRAM, IMAGE PROCESSING METHOD AND IMAGE PROCESSOR

摘要

An image processing apparatus (1) comprises: a cutoff frequency table (26) storing information on a relation between a parameter related to a radial intensity distribution of two-dimensional frequency components of a projection image and a Butterworth filter cutoff frequency to be applied to the projection image concerned; a projection image data input unit (10) for inputting projection image data; an FFT unit (20) for applying a two-dimensional Fourier transform to the projection image to obtain a spatial frequency of the projection image; a radial intensity distribution calculation unit (22) for calculating a radial intensity distribution of frequency components of the projection image; a cutoff frequency setting unit (24) for setting a cutoff frequency corresponding to a parameter related to the radial intensity distribution determined for the projection image, with reference to the cutoff frequency table; and a Butterworth filter (12) for filtering the projection image data with the set cutoff frequency. Consequently, an optimum cutoff frequency can be set automatically to perform filtering.