Three-dimensional surface representation using connectivity method without leaks

• US 4,905,148 A
• Filed: 08/04/1988
• Issued: 02/27/1990
• Est. Priority Date: 08/04/1988
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Crawford, Carl R.
• Primary Examiner(s): Jablon, Clark A.
• Application Number:
  US07/228,404
• Time in Patent Office: 572 Days
• Field of Search: 364/413.13, 382/26, 382/27, 382/16, 378/901
• US Class Current: 382/131
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

Objects within a three-dimensional tomographic data set which occupy the same portion of the image histogram are separated prior to three-dimensional surface extraction by applying connectivity first to unwanted objects. The unwanted objects thus identified are modified so that they no longer occupy the same portion of the histogram or are flagged. Next, connectivity is applied to the desired objects using a criterion different from the one used on the unwanted objects.

Claims

1. A method for generating a three-dimensional surface definition of an object-of-interest within a three-dimensional tomographic data set, said data set including a plurality of voxel data points, each voxel having a respective density value, said object-of-interest including voxels having density values satisfying a predetermined property, said method comprising the steps of:

identifying a non-object seed voxel in said data set not in said object-of-interest and having a density value satisfying said property;

applying connectivity to said non-object seed voxel according to a first criterion C₁ ;

modifying the density value of each voxel satisfying connectivity according to C₁ ;

specifying an object-of-interest seed voxel; and

applying connectivity to said object-of-interest seed voxel according to a second criterion C₂, where C₁ is not equal to C₂.

2. The method of claim 1 wherein C₁ defines a neighbor of a voxel differently than C₂.

3. The method of claim 2 wherein C₁ is anisotropic and wherein C₂ defines a three-dimensional connectivity.

4. The method of claim 2 wherein C₁ defines a two-dimensional connectivity and wherein C₂ defines a three-dimensional connectivity.

5. The method of claim 1 wherein said predetermined property is a range of density values.

6. Apparatus for generating a three-dimensional surface definition of an object-of-interest within a three-dimensional tomographic data set, said data set including a plurality of voxel data points, each voxel having a respective density value, said object-of-interest including voxels having density values satisfying a predetermined property, said apparatus comprising:

seed means for specifying an object seed voxel in said object-of-interest and a non-object seed voxel outside said object-of-interest and having said predetermined property;

connectivity means coupled to said seed means for applying connectivity to said non-object seed voxel according to a first criterion C₁, and for subsequently applying connectivity to said object seed voxel according to a second criterion C₂ ; and

modifying means coupled to said connectivity means for changing, prior to application of criterion C₂, the value of each voxel satisfying connectivity according to C₁ to a value not satisfying said predetermined property.

7. The apparatus of claim 6 wherein said predetermined property is a range of density values and wherein said apparatus further comprises range means for specifying said range.