Imaging system and method for use of same to determine metric scale of imaged bodily anatomy

• US 9,367,914 B2
• Filed: 05/16/2013
• Issued: 06/14/2016
• Est. Priority Date: 05/16/2012
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Hager, Gregory D., Ishii, Masaru, Meisner, Eric M., Marota, Daniel J., Tokgozoglu, Haluk N.
• Primary Examiner(s): Leubecker, John P
• Assistant Examiner(s): Torres Diaz, Arnaldo
• Application Number:
  US13/895,813
• Publication Number:
  US 20130321583A1
• Time in Patent Office: 1,125 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics
• CPC Class Codes: G06T 2200/08 involving all processing steps from image acquisition to 3D model generation
• CPC Class Codes: G06T 2207/10068 Endoscopic image
• CPC Class Codes: G06T 2207/20076 Probabilistic image processing
• CPC Class Codes: G06T 2207/30061 Lung
• CPC Class Codes: G06T 2207/30241 Trajectory
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 2210/41 Medical
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/579 from motion
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: H04N 13/20 Image signal generators

Abstract

Repositionable imaging system and method for creating a 3D image of a closed cavity of a patient'"'"'s anatomy containing the imaging system, estimating characteristics of motion of the system within the cavity, and determining a metric dimension characterizing the cavity without the use of mechanical measurement. The system may include tracking device located externally with respect to the cavity to determine a scale measurement of the system'"'"'s motion and the structure of the cavity. The system'"'"'s computer processor is configured to determine triangulated features of the cavity and recover motion scale data with the use of data received from the tracking device. A specific imaging system includes an endoscope (equipped with an electrical coil and complemented with an external electromagnetic tracker).

Claims

1. A method for determining geometrical characteristics of a closed cavity associated with a tissue with the use of an imaging system, the method comprising:

at a data-processing unit of the imaging system, receiving first data acquired by an optical camera of the imaging system, the camera being repositionable within the closed cavity, the first data representing the closed cavity on a process-determined scale associated with the closed cavity;

tracking repositioning of the camera in three-dimensional (3D) space with the use of a tracking element of the imaging system to generate second data representing position and orientation of the camera in 3D, the tracking element being in operable communication with the data-processing unit;

and

with the data-processing unit, recovering a true metric scale of the closed cavity based on the first and second data, the data-processing unit being programmed to derive position and orientation of the camera with respect to a camera'"'"'s reference frame, the true metric scale representing results of absolute measurement of said geometrical characteristics.

2. A method according to claim 1, further comprising determining structure of the closed cavity on a true geometrical scale and with respect to the derived position and orientation of the camera.

3. A method according to claim 1, further comprising producing a visually-perceivable representation of a structure of the closed cavity in reference to the recovered metric scale.

4. A method according to claim 1, wherein the method is devoid of using x-ray radiation and sizing the closed cavity with the use of a mechanical means.

5. A method according to claim 1, further comprising processing the first data to recover features that are capable of being matched to detect the repositioning of the camera in reference to a view of a surface of the closed cavity.

6. A method according to claim 5, wherein said processing of the first data includes determination of the surface of the closed cavity based at least in part on intensity of light characterizing the surface in reflectance, the determination including adjusting of surface properties that have been computed with the use of said features to define a recovered surface and computation of geometry of local patches of the surface.

7. A method according to claim 6, further comprising combining the recovered surface and computed geometry of local patches to form the surface of the closed cavity.

8. A method according to claim 1, wherein the camera includes a camera associated with an endoscope unit that has been positioned in a tubular bodily cavity, and wherein the geometrical characteristics include a diameter of the tubular bodily cavity graded on the recovered true geometrical scale.

9. An imaging system enabled to generate an image representing a closed bodily cavity, the imaging system comprising:

an optical camera configured to acquire first data from inside the closed cavity, the acquired first data representing a three-dimensional (3D) structure of said closed cavity on a local topographical scale, the optical camera being enabled to move with respect to the closed cavity;

a tracking device in operable communication with the optical camera and enabling an acquisition of second data that represents repositioning of the optical camera with respect to the closed cavity; and

a computer processor in operable cooperation with the optical camera and the tracking element, the computer processor programmed to

recover a true metric scale associated with geometry of the closed cavity based on the first and second data; and

determine geometrical characteristics of the closed cavity based on the 3D structure of the closed cavity and with respect to recovered true metric scale, the recovered true metric scale representing results of absolute measurement of said geometrical characteristics.

10. An imaging system according to claim 9, further comprising a display device, and wherein the computer processor is further programmed to cause a formation, on the display device, of a visually-perceivable rendering of the closed cavity, said rendering formed in correspondence with the determined geometrical characteristics.

11. An imaging system according to claim 9, wherein the computer processor is further programmed to:

identify scale-invariant features of the closed cavity based on stereo-triangulation of the first data; and

determine a three-dimensional (3D) surface of a portion of the closed cavity based on image intensity data from the first data and the identified scale-invariant features.

12. An imaging system according to claim 11, wherein the computer processor is further programmed to recover a metric scale of motion of the optical camera within the closed cavity based on the second data and to determine a geometrical measure associated with the closed cavity based on the recovered metric scale and the determined 3D surface.

13. An imaging system according to claim 9, further comprising an elongated body,

wherein the optical camera is housed inside the elongated body, and wherein a portion of the tracking device includes an electrical coil juxtaposed with the elongated body.

14. A method for forming a three-dimensional (3D) rendering a closed cavity of a patient'"'"'s anatomy, comprising:

acquiring a series of images of the closed cavity with an imaging system repositionably located therein, different images from the series corresponding to different positions of the imaging system;

determining a motion of the imaging system based on the images from the series with a data-processing system that is operably cooperated with the imaging system;

computing a graded dimension of the closed cavity based on a metric scale of the motion of the imaging system that has been determined based at least in part on data representing the repositioning of the imaging system and acquired with the use of a tracking device located externally with respect to the closed cavity; and

forming the 3D image of at least a portion of the closed cavity in proportion to the computed graded dimension.

15. A method according to claim 14, further comprising

based on the data received from the tracking device that is enabled to track at least one of orientation and position of the imaging system in relation to the closed cavity, determining the metric scale of the motion of the imaging system.

16. A method according to claim 14, wherein the determining the metric scale includes determining the metric scale based on the data received from at least one of an electromagnetic tracker, an accelerometer, a gyroscope, and an optical tracker.

17. A method according to claim 14, further comprising determining a structure associated with the closed cavity based on the determined motion of the imaging system and the data representing the repositioning of the imaging system.