| 摘要 |
PURPOSE:To extract a tumor shadow in a radiograph with high accuracy by scanning an image by using a real space filter by which the feature quantity whose value is different in accordance with whether a prescribed picture element for constituting the image is a picture element in the tumor shadow or not. CONSTITUTION:When an accumulative phosphor sheet 14 in which an X-ray image is recorded is set to a prescribed position of an X-ray image reader 20, and a stimulated luminous light 29 is allowed to diverge from the part irradiated with an excitation light 24 of the sheet 14, it is detected by a photomultiplier 31. An analog output signal SO outputted from the photomultiplier 31 is amplified by a logarithmic amplifier 32, digitized by an A/D converter 33, and image data S1 being an electric signal is obtained. This image signal S1 is inputted to a computer system 40, and a tumor shadow on the X-ray image is extracted. In this case, in order to derive the feature quantity whose value is different in accordance with whether a prescribed image PO used by a feature quantity arithmetic means in the computer system 40 is a picture element in the tumor shadow or not, the tumor shadow is extracted by scanning on the X-ray image by using a filter drawn virtually, for instance, centering around the prescribed image PO on the X-ray image. |
