Method and apparatus for image positioning processing

• US 6,714,680 B1
• Filed: 06/02/2000
• Issued: 03/30/2004
• Est. Priority Date: 06/02/1999
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Sasada, Ryoji
• Primary Examiner(s): Mariam, Daniel
• Assistant Examiner(s): GORADIA, SHEFALI DINESH
• Application Number:
  US09/585,471
• Time in Patent Office: 1,397 Days
• Field of Search: 382/132, 382/284, 382/130, 382/131, 382/209, 382/291, 382/216, 382/151, 250/581, 250/582, 250/584, 250/363.01, 250/363.02
• US Class Current: 382/216
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/30004 Biomedical image processing
• CPC Class Codes: G06T 7/32 using correlation-based methods

Abstract

Radiation images recorded serially on a plurality of sheets overlapping partially are positioned accurately. An image positioning processing apparatus comprises overlap area detection means for detecting an overlap area between two radiation images overlapping partially, rotation correction means for rotating, based on the overlap area, a lower image out of the two images, template setting means for setting a plurality of templates within the overlap area of the lower image, rank setting means for setting a reliability rank for each of the templates, matching position determining means for determining, based on the ranks of the templates, a matching position at which an image portion within each of the templates almost matches up with an image portion within the overlap area of an upper image, and positioning means for carrying out positioning of the two images based on the matching position having been determined.

Claims

1. An image positioning processing method for positioning two or more images overlapping at least partially to reconstruct an image, and the method comprising the steps of:

setting, on one of two images to be positioned, at least two positioning templates in an overlap area where the one image and the other image overlap at least partially;

setting a reliability rank for each of the templates representing adequacy as a template;

determining, based on the reliability rank, a matching position where an image portion of the one image in each of the templates almost matches up with an image portion of the other image in the overlap area; and

positioning the two images based on the matching position having been determined,

wherein said at least two positioning templates at least partially overlap.

2. An image positioning processing method as claimed in claim 1, further comprising the steps of:

selecting one or more templates the reliability ranks of which are high from the two or more templates prior to determining the matching position; and

determining the matching position based on the one or more templates having been selected.

3. An image positioning processing method as claimed in claim 2, further comprising the steps of:

presetting a search range of each of the templates having been selected, within the overlap area in the other image;

finding a degree of matching at each position within the search range having been preset for each of the templates while independently moving, within the search range, the template corresponding to the range;

selecting a position at which the degree of matching is highest for each of the templates; and

determining, as the matching position, a position frequently selected out of the positions selected for each of the templates.

4. An image positioning processing method as claimed in claim 1, further comprising the steps of:

presetting a search range of each of the templates within the overlap area in the other image;

finding a degree of matching at each position within the search range having been preset for each of the templates while independently moving, within the search range, the template corresponding to the search range;

selecting, for each of the templates, a position at which the matching degree is high; and

determining, as the matching position, a position frequently selected out of the positions selected for each of the templates, by weighting selection of the positions found by using each of the templates the reliability rank of which is high.

5. An image positioning processing method as claimed in any one of claims 1 to 4, wherein the reliability rank is set based on a variance of the image portion within the template.

6. An image positioning processing method as claimed in claim 1, further comprising the steps of:

presetting a search range of each of the templates within the overlap area in the other image;

finding a degree of matching at each position within the search range having been preset for each of the templates while independently moving, within the search range, the template corresponding to the search range;

setting the reliability rank for each of the templates based on a maximum matching degree or how the maximum matching degree peaks;

selecting, for each of the templates, a position at which the matching degree is high; and

determining, as the matching position, a position frequently selected out of the positions selected for each of the templates, by weighting selection of the positions found by using each of the templates the reliability rank of which is high.

7. An image positioning processing method as claimed in any one of claims 1-4 and 6, further comprising the step of:

rotating at least one of the images prior to setting the templates so that a relative tilt between the two images is corrected based on the overlap area.

8. An image positioning processing method as claimed in any one of claims 1-4 and 6, wherein

the two images are two radiation images obtained by separately reading two stimulable phosphor sheets overlapping at least partially and recording a radiation image of a subject.

9. An image positioning processing method as claimed in any one of claims 1-4 and 6, further comprising the steps of:

detecting a boundary image in an overlap portion of a first radiation image obtained by reading a first stimulable phosphor sheet placed farther from the subject upon photographing and overlapping with a second stimulable phosphor sheet placed closer to the subject; and

detecting the overlap area based on the boundary image having been detected.

10. An image positioning processing apparatus for positioning two or more images overlapping at least partially, in order to reconstruct an image, the apparatus comprising:

template setting means for setting, on one of two images to be positioned, at least two positioning templates in an overlap area where the one image and the other image overlap at least partially;

rank setting means for setting a reliability rank for each of the templates representing adequacy as a template;

matching position determining means for determining, based on the reliability rank, a matching position where an image portion of the one image in each of the templates almost matches up with an image portion of the other image in the overlap area; and

positioning means for positioning the two images based on the matching position having been determined,

wherein said at least two positioning templates at least partially overlap.

11. An image positioning processing apparatus as claimed in claim 10, further comprising template selection means for selecting one or more templates the reliability ranks of which are high, from the two or more templates, wherein

the matching position determining means determines the matching position based on the one or more templates having been selected.

12. An image positioning processing apparatus as claimed in claim 11, wherein the matching position determining means determines the matching position according to the steps of:

presetting, within the overlap area of the other image, a search range for each of the templates having been selected by the template selection means;

finding a matching degree at each position within the search range having been set while independently moving each template corresponding to the range;

selecting, for each of the templates, a position at which the matching degree is highest; and

determining, as the matching position, a position frequently selected out of the positions selected for each of the templates.

13. An image positioning processing apparatus as claimed in claim 10, wherein the matching position determining means determines the matching position according to the steps of:

presetting the search range for each of the templates within the overlap area of the other image;

finding a matching degree at each position within the search range having been preset while independently moving, within the search range, the template corresponding to the range;

selecting, for each of the templates, a position at which the matching degree is high;

weighting selection of the position by each of the templates the reliability rank of which is high, out of the positions selected for each of the templates; and

determining, as the matching position, a position frequently selected.

14. An image positioning processing apparatus as claimed in any one of claims 10 to 13, wherein the rank setting means sets the reliability rank based on a variance of the image portion within the template.

15. An image positioning processing apparatus according to claim 10, wherein the matching position determining means determines the matching position according to the steps of:

presetting, within the overlap area in the other image, the search range for each of the templates;

finding a matching degree at each position within the search range having been preset for each of the templates, while independently moving, within the search range, the template corresponding to the range;

selecting, for each of the templates, a position where the matching degree is high;

weighting selection of the position for each of the templates the reliability rank of which is high, from the positions selected for each of the templates; and

determining as the matching position, a position frequently selected, and the rank setting means sets the reliability rank of each of the templates in accordance with a maximum of the matching degree or how the matching degree peaks found for each of the templates by the matching position determining means.

16. An image positioning processing apparatus as claimed in any one of claims 10-13 and 15, further comprising rotation correction means for rotating at least one of the two images prior to setting the templates so that a relative tilt between the two images is corrected based on the overlap area.

17. An image positioning processing apparatus as claimed in any one of claims 10-13 and 15, wherein the two images are two radiation images obtained by separately reading two stimulable phosphor sheets at least partially overlapping and storing an image of a subject.

18. An image positioning processing apparatus as claimed in any one of claims 10-13 and 15, further comprising overlap area detection means for detecting a boundary image in an overlap portion of a first radiation image obtained by reading a first stimulable phosphor sheet located farther from the subject upon photographing and overlapping with a second stimulable phosphor sheet located closer to the subject, and for detecting the overlap area based on the overlap area having been detected.