| 摘要 |
PURPOSE:To accurately determine a desired picture signal range by extracting picture signals at points on the outline of a radiation shielding material to generate a histogram and determining the signal range on the higher density side than a specific signal value determined by the maximum frequency point of this histogram as the desired picture signal range bearing a part other than the radiation shielding material. CONSTITUTION:A radiation shielding material packed area K of a radiography has a density considerably lower than that of the other part. That is, since a considerable density difference is generated in an outline part E of the radiation shielding material, the absolute values of the differential value of points on the outline of the radiation shielding material normally take remarkably large values. In the histogram of picture signals related to points where absolute values of differential values exceed a prescribed threshold, the signal whose signal value is a maximum frequency point bears the density on the boundary. Thus, the range on the higher density side than this signal value is the signal range bearing the desired part. |
