# US 4,394,737 A · Method of processing radiographic image > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,394,737 A - Document ID: US4394737A - Status: Granted - Kind: A - Application number: 06/168,802 - Filed: 1980-07-11 - Granted: 1983-07-19 - Earliest claimed: 1979-07-11 - Assignees: Fuji Photo Film Co., Ltd. - Inventors: Takao Komaki; Seiji Matsumoto - Web page: https://patentgrep.com/patent/US4394737A ## CPC - H05G 1/60: Circuit arrangements for obtaining a series of X-ray photographs or for X-ray cinematography - G03C 5/16: X-ray, infrared, or ultraviolet ray processes - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) - G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G) ## Abstract In radiography, a plurality of radiographic films are used for recording radiographic images of an object viewed from the same direction. For instance, a stack of radiographic films stacked together with intensifying screens is exposed to X-rays passing through an object to record the images on the films simultaneously. Alternatively, the plurality of radiographic films are exposed to X-rays passing through the object one by one with the object held still at a position. The images on the plurality of radiographic films are superposed together by electrical signal processing means to obtain an image having averaged density. Then, the gradient of the gradation of the averaged image is enhanced. The radiographic films may be stacked together with self-supporting intensifying screens to reduce the thickness of the stack of the films and intensifying screens when recording the radiographic images. Further, double-side coated intensifying screens may be used together with the stack of the films to reduce the thickness of the stack of the films and intensifying screens when recording the radiographic images. ## Claims ### Claim 1 In radiographic image recording system, a method of processing a radiographic image comprising steps of recording radiographic images of an object viewed from the same direction on a plurality of radiographic films, superposing and averaging the images on the plurality of radiographic films to obtain an averaged image having averaged density, and enhancing the gradient of gradation of the averaged image. ### Claim 2 (depends on 1) A method of processing a radiographic image according to claim 1 wherein said radiographic images of an object are recorded on the plurality of radiographic films sequentially. ### Claim 3 (depends on 1) A method of processing a radiographic image according to claim 1 wherein said radiographic images of an object are recorded on the plurality of radiographic films simultaneously. ### Claim 4 (depends on 3) A method of processing a radiographic image according to claim 3 wherein said radiographic images of an object are recorded on a stack of the plurality of radiographic films simultaneously. ### Claim 5 (depends on 1, 2, 3) A method of processing a radiographic image according to one of claims 1, 2, 3, and 4 wherein said images are recorded by a slit recording method. ### Claim 6 A method of processing a radiographic image in a radiographic image recording system comprising steps of recording radiographic images of an object viewed from the same direction on a plurality of radiographic films, superposing and averaging the images on the plurality of radiographic films to obtain an averaged image having averaged density, obtaining an unsharp mask density Dus corresponding to a super-low frequency of said averaged image, and performing an operation represented by a formula of Dorg+.beta.(Dorg-Dus) where Dorg is the density of the image and .beta. is an emphasis coefficient, whereby the gradient of gradation of the averaged image is enhanced with respect to a frequency component above said super-low frequency. ### Claim 7 (depends on 6) A method according to claim 6 wherein said radiographic images of an object are recorded on the plurality of radiographic films sequentially. ### Claim 8 (depends on 6) A method according to claim 6 wherein said radiographic images of an object are recorded on the plurality of radiographic films simultaneously. ### Claim 9 (depends on 8) A method of processing a radiographic image according to claim 8 wherein said radiographic images of an object are recorded on a stack of the plurality of radiographic films simultaneously. ### Claim 10 (depends on 6, 7, 8) A method of processing a radiographic image accordingn to one of claims 6, 7, 8, and 9 wherein said operation is performed by use of an unsharp mask having a modulation transfer function which falls below 0.5 in the super-low frequency range of 0.5 to 0.01 cycle/mm. ### Claim 11 (depends on 6, 7, 8) A method of processing a radiographic image according to one of claims 6, 7, 8, and 9 wherein said emphasis coefficient .beta. is changed according to the original density Dorg of the image or the unsharp mask density Dus of the image. ### Claim 12 (depends on 6, 7, 8) A method of processing a radiographic image according to one of claims 6, 7, 8, and 9 wherein said images are recorded by a slit recording method. ### Claim 13 A method of processing a radiographic image in a radiographic image recording system comprising steps of recording radiographic images of an object viewed from the same direction on a plurality of radiographic films, superposing and averaging the images on the plurality of radiographic films to obtain an averaged image having averaged density, obtaining an unsharp mask density Dus corresponding to a super-low frequency of said radiographic images on the radiographic films, and performing an operation represented by a formula of Dorg+.beta.(Dorg-Dus) where Dorg is the density of the image and .beta. is an emphasis coefficient, whereby the gradient of gradation of the averaged image is enhanced with respect to a frequency component above said super-low frequency.