Apparatus and method for detecting an edge of three-dimensional image data

• US 20030076317A1
• Filed: 07/19/2002
• Published: 04/24/2003
• Est. Priority Date: 10/19/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jae-chool
• Granted Patent: US 6,900,801 B2
• Time in Patent Office: Days
• US Class Current: 345/419
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 2200/04 involving 3D image data
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/12 Edge-based segmentation

Abstract

An apparatus and a method for detecting an edge of a three-dimensional image. A scan-line approximation unit creates an approximated quadratic curve with regard to each scan-line corresponding to each surface of the three-dimensional image by scanning the three-dimensional image in several directions of a row, a column and both diagonal lines. A curvature value calculation unit calculates approximated curvature values with regard to each division point regarded as different surfaces of the three-dimensional image on the quadratic curve. An edge decision unit decides an edge by comparing the calculated curvature values of the division points with a threshold. According to the above apparatus and the method for detecting the edge of the three-dimensional image, both a jump edge and a crease edge can be detected through one threshold. The method of detecting the edge can detect all edges according to the characteristic of the object of the three-dimensional image by using one threshold, thus the edge can be quickly and more accurately detected. Furthermore, the capability of the entire system can be improved by using information gained during the process of detecting the edge in a pre-process and a post-process.

Claims

1. An apparatus for detecting an edge in a three-dimensional image, comprising:

a scan-line approximation unit creating an approximated quadratic curve with regard to each scan-line corresponding to each surface of the three-dimensional image by scanning the three-dimensional image in a set-up direction;

a curvature value calculation unit calculating approximated curvature values with regard to each division point estimated as different surfaces of the three-dimensional image on the quadratic curve approximated from the scan-line approximation unit; and

an edge decision unit deciding an edge by comparing the approximated curvature values of the division points calculated from the curvature value calculation unit with a predetermined threshold.

2. The apparatus according to claim 1, wherein scans of the scan-line approximation unit are performed in a plurality of directions.

3. The apparatus according to claim 1, wherein scan directions of the scan-line approximation unit are at least one of a row direction, a column direction, and a diagonal direction.

4. The apparatus according to claim 1, wherein the curvature calculation unit calculates the curvature values of the division points through a mathematical expression represented by;

9. The apparatus according to claim 2, wherein the scans of the scan-line approximation unit are performed in parallel.

14. The apparatus according to claim 1, wherein the determination unit calculates the curvature values of the division points through a mathematical expression represented by;

5. A method of detecting an edge of a three-dimensional image, comprising:

creating an approximated quadratic curve with regard to each scan-line corresponding to each surface of the three-dimensional image by scanning the three-dimensional image in a set-up direction;

calculating approximated curvature values with regard to each division point regarded as different surfaces of the three-dimensional image on the approximated quadratic curve; and

deciding an edge by comparing the curvature values of the division points with a predetermined threshold.

6. The method according to claim 5, further comprising:

scanning in a plurality of directions.

7. The method according to claim 5, further comprising:

scanning in at least one of a row direction, a column direction, and a diagonal direction.

8. The method according to claim 5, wherein the curvature values of the division points is calculated in the curvature value calculating represented by a mathematical expression;

10. The method according to claim 7, wherein said scanning of more than one direction is provided in parallel.

11. An apparatus for detecting an edge in a three-dimensional image by determination of division points of different surfaces of the three three-dimensional image by scanning in a first direction and calculating approximated curvature values, the apparatus comprising:

a determination unit determining the division points estimated as the different surfaces of the three-dimensional image based on a curve according to each scan-line corresponding to a surface of the three-dimensional image scanned in the first direction and calculating the approximated curvature values from each division point; and

an edge decision unit deciding an edge by comparing the approximated curvature values of the determined division points with a predetermined threshold.

12. The apparatus according to claim 11, wherein scans of the determining unit are performed in a plurality of directions.

13. The apparatus according to claim 11, wherein scan directions of the determining unit are in at least one of a row direction, a column direction, and a diagonal direction.

15. The apparatus according to claim 12, wherein the scans of the scan-line approximation unit are performed in parallel.

16. A method of detecting an edge in a three-dimensional by determination of division points of different surfaces of the three-dimensional image, the apparatus comprising:

determining the division points estimated as the different surfaces of the three-dimensional image based on a curve according to each scan-line corresponding to a surface of the three-dimensional image scanned in a first direction;

calculating approximated curvature values from each division point of said determining; and

deciding an edge by comparing the approximated curvature values of the determined division points with a predetermined threshold.

17. The method according to claim 16, further comprising:

scanning in a plurality of directions.

18. The method according to claim 16, further comprising:

scanning in at least one of a row direction, a column direction, and a diagonal direction.

19. The method according to claim 16, wherein the curvature values of the division points is calculated in the curvature value calculating represented by a mathematical expression;

20. The method according to claim 18, wherein said scanning of more than one direction is provided in parallel.

21. An apparatus for detecting both jump edges and cease edges in a three-dimensional image by determination of each of the jump edges and each of the cease edges as one of a plurality of division points of different surfaces of the three-dimensional image by scanning in a first direction and calculating approximated curvature values, the apparatus comprising:

a determination unit determining each of the jump edges and each of the cease edges as one of the plurality of the division points, the division points representing the different surfaces of the three-dimensional image based on a curve according to each scan-line corresponding to a surface of the three-dimensional image scanned in the first direction and calculating the approximated curvature values from each division point; and

an edge decision unit deciding each of the jump edges and each of the cease edges by comparing the approximated curvature values of the determined division points with one threshold value.

22. A method of detecting both jump edges and cease edges in a three-dimensional by determination of each of the jump edges and each of the cease edges as one of a plurality of division points of different surfaces of the three-dimensional image, the apparatus comprising:

determining each of the jump edges and each of the cease edges as one of the plurality of the division points representing the different surfaces of the three-dimensional image based on a curve according to each scan-line corresponding to a surface of the three-dimensional image scanned in a first direction;

calculating approximated curvature values from each division point of said determining; and

deciding each of the jump edges and each of the cease edges by comparing the approximated curvature values of the determined division points with one threshold value.