| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a periodic pattern if an irradiation field area further includes an area where the periodic pattern can be hardly detected.SOLUTION: An image acquisition unit 31 acquires a radiation image P0 from a radiation detector 2, and an irradiation field detection unit 32 detects an irradiation field area P1 from the radiation image P0. An analysis area setting unit 33 detects a direct radiation area, a high absorber area and a high noise area as areas where a probability of presence of periodic patterns is low. An analysis area P2 is set by excluding these areas from the irradiation field area P1. A frequency analysis unit 34 analyzes a frequency only for the analysis area P2, and detects frequency components of a periodic pattern caused by a grid. A filtering processing unit 35 removes the frequency components of the periodic pattern caused by the grid from the radiation image P0. |
