Patent Number: 
Section: claims

1. An X-ray imaging system comprising:a radiographing device comprising an X-ray irradiator and an X-ray receiver positioned opposite said X-ray irradiator across an imaging space, said radiographing device configured to radiograph a subject positioned between said X-ray irradiator and said X-ray receiver;an optical radiographing device configured to detect an optical image of the subject;a specifying device configured to analyze the optical image and to specify physical characteristics of the subject; anda positioning device configured to position said X-ray irradiator and said X-ray receiver based on the specified physical characteristics and a portion of the subject to be radiographed. 2. An X-ray imaging system according to claim 1, wherein said radiographing device further comprises:a first support device configured to movably support said X-ray irradiator in two horizontal directions orthogonal to each other and in a vertical direction and to rotatably support said X-ray irradiator about two axes orthogonal to each other; anda second support device configured to support said X-ray receiver such that said X-ray receiver is vertically movable to facilitate changing a direction of a light receiving surface of said X-ray receiver. 3. An X-ray imaging system according to claim 2, wherein said first support device comprises an overhead tube suspension. 4. An X-ray imaging system according to claim 2, wherein said second support device comprises a wall stand. 5. An X-ray imaging system according to claim 1, wherein said radiographing device further comprises:a first support device configured to movably support said X-ray irradiator in two horizontal directions orthogonal to each other and in a vertical direction and to rotatably support said X-ray irradiator about two axes orthogonal to each other; anda table configured to support a top board as a vertically movable subject carrier and to support said X-ray receiver under the top board horizontally movably. 6. An X-ray imaging system according to claim 5, wherein said first support device comprises an overhead tube suspension. 7. An X-ray imaging system according to claim 1, wherein said X-ray receiver comprises a first X-ray receiver and a second X-ray receiver, and wherein said radiographing device further comprises:a first support device configured to movably support said X-ray irradiator in two horizontal directions orthogonal to each other and in a vertical direction and to rotatably support said X-ray irradiator about two axes orthogonal to each other;a second support device configured to support said X-ray receiver such that said X-ray receiver is vertically movable to facilitate changing a direction of a light receiving surface of said X-ray receiver; anda table configured to support a top board as a vertically movable subject carrier and to support said second X-ray receiver under the top board horizontally movably. 8. An X-ray imaging system according to claim 7, wherein said first support device comprises an overhead tube suspension. 9. An X-ray imaging system according to claim 7, wherein said second support device comprises a wall stand. 10. An X-ray imaging method comprising:picking up an optical image of the subject;analyzing the optical image and specifying physical characteristics of the subject;positioning an X-ray irradiator and an X-ray receiver based on the specified physical characteristics and a portion of the subject to be radiographed;radiographing the subject using the positioned X-ray irradiator and X-ray receiver. 11. An X-ray imaging method according to claim 10, wherein positioning an X-ray irradiator comprises positioning the X-ray irradiator by displacement in two horizontal directions orthogonal to each other and in a vertical direction and by rotation about two axes orthogonal to each other. 12. An X-ray imaging method according to claim 11, wherein the X-ray irradiator is supported by an overhead tube suspension. 13. An X-ray imaging method according to claim 10, wherein positioning an X-ray receiver comprises positioning the X-ray receiver by displacement in a vertical direction to facilitate changing a direction of a light receiving surface of the X-ray receiver. 14. An X-ray imaging system according to claim 13, wherein the X-ray receiver is supported by a wall stand. 15. An X-ray imaging method according to claim 10, wherein the X-ray receiver is provided under a top board as a subject carrier, and wherein positioning the X-ray receiver comprises displacing the X-ray receiver horizontally under the top board. 16. An X-ray imaging method according to claim 10, wherein the X-ray receiver includes a first X-ray receiver and a second X-ray receiver, and wherein positioning the X-ray receiver comprises positioning the first X-ray receiver and the second X-ray receiver respectively. 17. An X-ray imaging method according to claim 16, wherein positioning the first X-ray receiver comprises positioning the first X-ray receiver by displacement in a vertical direction to facilitate changing a direction of a light receiving surface of the first X-ray receiver. 18. An X-ray imaging system according to claim 17, wherein the X-ray receiver is supported by a wall stand. 19. An X-ray imaging method according to claim 16, wherein the second X-ray receiver is provided under a top board as a subject carrier, and wherein positioning the second X-ray receiver comprises displacing the second X-ray receiver horizontally under the top board. 20. An X-ray imaging method according to claim 10, wherein the X-ray irradiator is supported by an overhead tube suspension.