Image registration apparatus, image registration method, and image registration program
An image registration apparatus includes an image acquisition unit that acquires a three-dimensional image obtained by imaging a subject and an image different from the three-dimensional image; a graph structure generation unit that generates a graph structure of a tubular structure included in the three-dimensional image; a contour information acquisition unit that acquires contour information of the tubular structure at each point on the graph structure; and a registration unit that performs registration between the three-dimensional image and the different image on the basis of the contour information.
1. An image registration apparatus comprising:
an image acquisition unit that acquires a three-dimensional image obtained by imaging a subject and an image different from the three-dimensional image;
a graph structure generation unit that generates a graph structure of a tubular structure included in the three-dimensional image;
a contour information acquisition unit that acquires contour information of the tubular structure at each point on the graph structure; and
a registration unit that performs registration between the three-dimensional image and the different image on the basis of the contour information, the different image is the image different from the three-dimensional image.
2. The image registration apparatus according to claim 1 ,
wherein the different image is an actual endoscope image acquired using an endoscope inserted in the tubular structure.
3. The image registration apparatus according to claim 2 , further comprising:
a visual point information acquisition unit that acquires visual point information inside the tubular structure;
a projection point specification unit that specifies a projection point from respective points on the graph structure on the basis of the visual point information and the graph structure; and
a projection image generation unit that generates a projection image obtained by projecting the contour information at the projection point on a two-dimensional plane,
wherein the registration unit performs registration between the three-dimensional image and the different image using the projection image.
4. The image registration apparatus according to claim 3 ,
wherein the projection point specification unit specifies one point on the graph structure as a starting point, specifies points included in a predetermined range as projection candidate points while following the graph structure from the starting point, and specifies the projection point from the projection candidate points.
5. The image registration apparatus according to claim 2 , further comprising:
a visual point information acquisition unit that acquires visual point information inside the tubular structure;
a projection point specification unit that specifies a projection point from respective points on the graph structure on the basis of the visual point information and the graph structure;
a projection image generation unit that generates a projection image obtained by projecting the contour information at the projection point on a two-dimensional plane, and
a hole contour extraction unit that extracts a contour of a hole included in the actual endoscope image,
wherein the registration unit performs registration between the three-dimensional image and the different image using the projection image and the extracted contour of the hole.
6. The image registration apparatus according to claim 5 ,
wherein the projection point specification unit specifies one point on the graph structure as a starting point, specifies points included in a predetermined range as projection candidate points while following the graph structure from the starting point, and specifies the projection point from the projection candidate points.
7. The image registration apparatus according to claim 5 ,
wherein the projection point specification unit specifies the projection point on the basis of shape information of the contour information.
8. The image registration apparatus according to claim 1 ,
wherein the different image is a three-dimensional image, different from the three-dimensional image, obtained by imaging the subject.
9. The image registration apparatus according to claim 8 , further comprising:
a visual point information acquisition unit that acquires visual point information inside the tubular structure;
a projection point specification unit that specifies a projection point from respective points on the graph structure on the basis of the visual point information and the graph structure; and
a projection image generation unit that generates a projection image obtained by projecting the contour information at the projection point on a two-dimensional plane,
wherein the registration unit performs registration between the three-dimensional image and the different image using the projection image.
10. The image registration apparatus according to claim 9 ,
wherein the projection point specification unit specifies one point on the graph structure as a starting point, specifies points included in a predetermined range as projection candidate points while following the graph structure from the starting point, and specifies the projection point from the projection candidate points.
11. The image registration apparatus according to claim 1 , further comprising:
a visual point information acquisition unit that acquires visual point information inside the tubular structure;
a projection point specification unit that specifies a projection point from respective points on the graph structure on the basis of the visual point information and the graph structure; and
a projection image generation unit that generates a projection image obtained by projecting the contour information at the projection point on a two-dimensional plane,
wherein the registration unit performs registration between the three-dimensional image and the different image using the projection image.
12. The image registration apparatus according to claim 11 ,
wherein the projection point specification unit specifies one point on the graph structure as a starting point, specifies points included in a predetermined range as projection candidate points while following the graph structure from the starting point, and specifies the projection point from the projection candidate points.
13. The image registration apparatus according to claim 12 ,
wherein the projection point specification unit specifies the projection point on the basis of shape information of the contour information.
14. The image registration apparatus according to claim 11 ,
wherein the projection point specification unit specifies the projection point on the basis of shape information of the contour information.
15. The image registration apparatus according to claim 11 ,
wherein the projection image generation unit acquires information on a branch to which the projection point belongs and adds the information on the branch to the projection image.
16. The image registration apparatus according to claim 11 , further comprising:
a visual point information estimation unit that estimates visual point information of the different image on the basis of a result of the registration process between the projection image and the different image and visual point information of the projection image.
17. The image registration apparatus according to claim 1 ,
wherein the tubular structure is the bronchus.
18. An image registration method using the image registration apparatus according to claim 1 comprising:
acquiring the three-dimensional image obtained by imaging the subject and the image different from the three-dimensional image;
generating the graph structure of the tubular structure included in the three-dimensional image;
acquiring the contour information of the tubular structure at each point on the graph structure; and
performing registration between the three-dimensional image and the different image on the basis of the contour information.
19. A non-transitory computer readable recording medium storing an image registration program that causes a computer to function as the image registration apparatus according to claim 1 , the image registration program causes the computer to execute:
a process of acquiring the three-dimensional image obtained by imaging the subject and the image different from the three-dimensional image;
a process of generating the graph structure of the tubular structure included in the three-dimensional image;
a process of acquiring the contour information of the tubular structure at each point on the graph structure; and
a process of performing registration between the three-dimensional image and the different image on the basis of the contour information.
20. An image registration apparatus comprising:
a memory that stores a command to be executed by a computer; and
a processor configured to executed the stored command,
wherein the processor executes a process of acquiring a three-dimensional image obtained by imaging a subject and an image different from the three-dimensional image; a process of generating a graph structure of a tubular structure included in the three-dimensional image; a process of acquiring contour information of the tubular structure at each point on the graph structure; and a process of performing registration between the three-dimensional image and the different image on the basis of the contour information, the different image is the image different from the three-dimensional image.