Radiation image forming method and apparatus

• US 6,272,198 B1
• Filed: 10/29/1999
• Issued: 08/07/2001
• Est. Priority Date: 10/29/1998
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Shimura, Kazuo
• Primary Examiner(s): BRUCE, DAVID VERNON
• Application Number:
  US09/430,299
• Time in Patent Office: 648 Days
• Field of Search: 378/4, 378/7, 378/901
• US Class Current: 378/7
• CPC Class Codes: A61B 6/5258 involving detection or reduction of artifacts or noise
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A plurality of radiation image signals, which represent radiation images of an object, are obtained by irradiating radiation from different directions to the object and detecting the radiation carrying image information of the object via a scattered radiation removing device for removing radiation having been scattered by the object. Image signal components representing a pattern of the scattered radiation removing device, which are contained in the radiation image signals, are reduced, and pattern-reduced radiation image signals, in which the image signal components representing the pattern of the scattered radiation removing device have been reduced, are thereby obtained. At least either one of a volume signal and a tomographic image signal representing an image of the object is then obtained from the pattern-reduced radiation image signals.

Claims

1. A radiation image forming method, wherein at least either one of a volume signal and a tomographic image signal representing an image of an object is obtained from a plurality of radiation image signals, which represent radiation images of the object and which have been obtained by irradiating radiation from different directions to the object and detecting the radiation carrying image information of the object via scattered radiation removing means for removing radiation having been scattered by the object, the method comprising the steps of:

i) reducing image signal components representing a pattern of the scattered radiation removing means, which are contained in the radiation image signals, pattern-reduced radiation image signals, in which the image signal components representing the pattern of the scattered radiation removing means have been reduced, being thereby obtained, and

ii) obtaining at least either one of the volume signal and the tomographic image signal from said pattern-reduced radiation image signals.

2. A method as defined in claim 1 wherein the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, is performed by utilizing spatial-domain filtering processing.

3. A method as defined in claim 1 wherein the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, is performed by utilizing frequency-domain filtering processing.

4. A method as defined in claim 1 wherein the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, is performed by utilizing morphology filtering processing.

5. A radiation image forming apparatus comprising image signal forming means for obtaining at least either one of a volume signal and a tomographic image signal representing an image of an object from a plurality of radiation image signals, which represent radiation images of the object and which have been obtained by irradiating radiation from different directions to the object and detecting the radiation carrying image information of the object via scattered radiation removing means for removing radiation having been scattered by the object,

wherein the apparatus further comprises pattern reducing means for reducing image signal components representing a pattern of the scattered radiation removing means, which are contained in the radiation image signals, pattern-reduced radiation image signals, in which the image signal components representing the pattern of the scattered radiation removing means have been reduced, being thereby obtained, and

the image signal forming means obtains at least either one of the volume signal and the tomographic image signal from said pattern-reduced radiation image signals, which have been obtained from said pattern reducing means.

6. An apparatus as defined in claim 5 wherein said pattern reducing means performs the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, by utilizing spatial-domain filtering processing.

7. An apparatus as defined in claim 5 wherein said pattern reducing means performs the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, by utilizing frequency-domain filtering processing.

8. An apparatus as defined in claim 5 wherein said pattern reducing means performs the reducing of the image signal components representing the pattern of the scattered radiation removing means, which are contained in the radiation image signals, by utilizing morphology filtering processing.