Patent Number: 046882421
Section: claims

1. An X-ray imaging system comprising: an X-ray source for emitting X-rays to be radiated on an object;  X-ray image detection means for detecting an X-ray image emitted from said X-ray source and transmitted through said object;  X-ray mask means, having a plurality of X-ray shielding regions distributed in a predetermined pattern, for locally shielding X-rays with said plurality of X-ray shielding regions;  drive means for moving said X-ray mask means so that said X-ray mask means is inserted or removed with respect to an X-ray radiation field between said X-ray image detection means and said X-ray source and is sequentially positioned at a plurality of predetermined positions in said X-ray radiation field;  storage means for storing X-ray image data;  first calculating means, associated with said storage means, for calculating scattered X-ray intensity distribution data associated with said object based on a plurality of transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located at different positions in said X-ray radiation field, and on transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located outside said X-ray radiation field;  second calculating means, associated with said storage means, for calculating X-ray image data, from which the influence of scattered X-rays is eliminated, in accordance with the scattered X-ray intensity distribution data obtained by said first calculating means and transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located outside said X-ray radiation field; and  image output means for outputting the X-ray image data calculated by said second calculating means as a visible image. 2. A system according to claim 1, wherein said X-ray mask means is an X-ray mask member comprising a plate of an X-ray transmitting material, on which a plurality of X-ray shielding segments are adhered. 3. A system according to claim 2, wherein said X-ray shielding segments are lead segments. 4. A system according to claim 1, wherein said drive means is means for automatically moving said X-ray mask means to be interlocked with said X-ray source and said X-ray image detection means. 5. A system according to claim 1, wherein said X-ray image detection means includes X-ray/photo conversion means for converting X-ray data into visible image data, and camera means for converting an output image from said X-ray/photo conversion means into an electrical signal. 6. A system according to claim 5, wherein said X-ray/photo conversion means is an image intensifier. 7. A system according to claim 1, wherein said first calculating means calculates said scattered X-ray intensity distribution data with the use of an interpolation calculation technique utilizing a SINC function. 8. A system according to claim 1, wherein said first calculating means has means for identifying whether or not present transmission X-ray intensity data masked by said X-ray mask means is said scattered x-ray intensity data, in accordance with whether or not the intensity data exceeds a predetermined threshold level. 9. A system according to claim 1, wherein said storage means is a means having a memory area for transmission X-ray data obtained when said X-ray mask means is located in said X-ray radiation field which memory area is smaller per one frame than a memory area for transmission X-ray data which is obtained when said X-ray mask means is located outside the X-ray radiation field.