System and method for three-dimensional geometric modeling by extracting and merging two-dimensional contours from CT slice data and CT scout data

• US 6,028,907 A
• Filed: 05/15/1998
• Issued: 02/22/2000
• Est. Priority Date: 05/15/1998
• Status: Expired due to Term

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Wu, Chai Wah, Tresser, Charles P., Margulies, Joseph Y., Kalvin, Alan David, Adler, Roy Lee
• Primary Examiner(s): Bruce, David Vernon
• Application Number:
  US09/078,522
• Time in Patent Office: 648 Days
• Field of Search: 378/4, 378/901, 382/130, 382/131
• US Class Current: 378/4
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: A61B 6/505 for diagnosis of bone
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A computer system and method solve the problem of getting a useful three-dimensional representation of an object like the spine using a small amount of data. This is done by gathering three-dimensional data in the form of a set of 2D computer tomography (CT) slices of a patient'"'"'s bones and a coaxial set of 2D CT scout images, which are digital two-dimensional X-ray images that can be produced by a CT scanner; extracting from each of these three-dimensional data sets a corresponding stack of 2D contours; and constructing a 3D geometric model of the object. The main features of spinal deformation are captured by integrating these two sets of three-dimensional data, and constructing from them a three-dimensional geometric model of the spine. Scouts are usually used to monitor CT scan acquisition. Here, they are also used as an essential source of data.

Claims

1. A computer-implemented method of three-dimensional modeling of objects comprising the steps of:

collecting first and second sets of data, each of said first and second sets of data containing a limited amount of three-dimensional spatial data of a common three-dimensional object, where the amount of data in either of said first and second sets of data alone is not sufficient to produce an adequate three-dimensional geometric model of said common object;

extracting from said first set of data a stack of 2D convex contours;

extracting from said second set of data a stack of 2D contours;

merging the extracted stack of 2D convex contours from the first set of data with the extracted stack of 2D contours from the second set of data to form an integrated stack of 2D contours; and

generating a three-dimensional model of said common object from the integrated stack of 2D contours.

2. The computer-implemented method in claim 1 wherein the step of extracting a stack of 2D convex contours comprises the steps of:

extracting edges from the three-dimensional spatial data represented by the first set of data using an edge-detecting algorithm;

deriving tangents from the extracted edges; and

generating the stack of 2D convex contours from the derived tangents.

3. The computer-implemented method in claim 1 used for three-dimensional reconstruction of vertebral bodies of a spine by using a stack of 2D computer tomography (CT) slices and a set of coaxial 2D CT scout images as the two sets each having a limited amount of three-dimensional data of a common object, the set of CT slices and the set of CT scout images both having been obtained using a clinically acceptable amount of radiation.

4. A computer system used to improve the geometric modeling of three-dimensional objects by utilizing two complementary sets of three-dimensional data comprising:

a computer with a memory, a central processing unit (CPU), and a display monitor;

a first data structure resident in said memory and containing a limited amount of three-dimensional data of the shape of a three-dimensional object, where the amount of data in this first data set is not sufficient on its own to allow construction of a satisfactory geometric model of this three-dimensional object;

a second data structure resident in said memory and containing a limited amount of three-dimensional data of the shape of the said three-dimensional object, where the amount of data in this second data set is not sufficient on its own to allow construction of a satisfactory geometric model of this said three-dimensional object; and

a process executed by the CPU, to construct a three-dimensional model of the said object using both three-dimensional data sets, the process including extracting from said first data structure a stack of 2D convex contours, extracting from said second data structure a stack of 2D contours, merging the extracted stack of 2D convex contours from the first set of data with the extracted stack of 2D contours from the second set of data to form an integrated stack of 2D contours, and generating a three-dimensional model of said common object from the integrated stack of 2D contours.

5. A computer system as in claim 4 used to improve the geometric modeling of three-dimensional objects is used for three-dimensional reconstruction of vertebral bodies of a spine using a stack of 2D computer tomography (CT) slices and a set of coaxial 2D CT scout images as the two complementary sets of three-dimensional data.

6. A computer system as in claim 5 wherein the process executed by the CPU to construct a three-dimensional model of the object using both three-dimensional data sets includes computing a stack of 2D sinograms from a set of coaxial 2D scout images, determining sets of edges in said sinogram images, said edges corresponding to lines in 3D that are tangent to the object of interest being scanned by the CT scanner producing the said coaxial 2D scout images, and computing from said tangent lines a set of 2D convex contours, where each of the said 2D convex contours lies on the convex hull of a 2D cross-section of the said object of interest.