Method for recognizing three-dimensional control point and computer readable medium using the same thereof

• US 8,433,131 B2
• Filed: 07/19/2010
• Issued: 04/30/2013
• Est. Priority Date: 06/23/2010
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Liao, Chih-Pin, Tsai, Yao-Yang, Wang, Ko-Shyang, Huang, Jay
• Primary Examiner(s): Liew, Alex
• Application Number:
  US12/838,710
• Publication Number:
  US 20110317925A1
• Time in Patent Office: 1,016 Days
• Field of Search: 382/154
• US Class Current: 382/154
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 5/70 Denoising; Smoothing

Abstract

A method for recognizing three-dimensional control points and a computer readable medium using the same are disclosed. The method for recognizing three-dimensional control points comprises the following steps. A depth information item corresponding to an image captured by an image capturing apparatus is received. A three-dimensional block information item corresponding to a three-dimensional block is generated according to the depth information. At least one reference plane is generated according to the depth information. At least one connection group is generated according to the three-dimensional block information and the reference plane. A three-dimensional block nearest to the image capturing apparatus is selected as a control point from the connection group.

Claims

1. A method for recognizing three-dimensional control points, comprising:

receiving a depth information item corresponding to an image captured by an image capturing apparatus;

generating a plurality of three-dimensional block information items corresponding to a plurality of three-dimensional blocks according to the depth information;

generating at least one reference plane according to the depth information;

generating at least one connection group according to the three-dimensional block information and the reference plane; and

selecting a three-dimensional block nearest to the image capturing apparatus as a control point from the connection group;

wherein the step of generating a plurality of three-dimensional block information items comprises;

detecting a plurality of protrusions according to the depth information;

expanding the protrusions into the three-dimensional blocks according to the depth differences between the protrusions and the pixels surrounding the protrusions; and

generating the three-dimensional block information items corresponding to the three-dimensional blocks.

2. The method for recognizing three-dimensional control points according to claim 1, wherein the step of generating a plurality of three-dimensional block information items further comprises:

filtering noise blocks off the three-dimensional blocks according to depth change.

3. The method for recognizing three-dimensional control points according to claim 1, wherein the step of generating a plurality of three-dimensional block information items further comprises:

determining whether the protrusions are all checked;

if no, then the step of expanding the protrusions into the three-dimensional blocks is repeated.

4. The method for recognizing three-dimensional control points according to claim 1, wherein the step of generating a plurality of three-dimensional block information items further comprises:

determining a plurality of representative points from the three-dimensional blocks; and

generating the three-dimensional block information items corresponding to the representative points.

5. The method for recognizing three-dimensional control points according to claim 4, wherein the representative points respectively are the gravity points of the three-dimensional blocks.

6. The method for recognizing three-dimensional control points according to claim 1, wherein the step of generating at least one the reference plane comprises:

calculating a statistics of space distribution according to the depth information;

applying interval smoothing and overall weighting to the statistics of space distribution; and

filtering a noise plane off to generate the reference plane.

7. The method for recognizing three-dimensional control points according to claim 6, wherein the statistics of space distribution is the number of pixels corresponding to different depths.

8. The method for recognizing three-dimensional control points according to claim 6, wherein in the step of filtering a noise plane off to generate the reference plane, the reference plane is generated according to the highest peak value of the statistics of space distribution.

9. The method for recognizing three-dimensional control points according to claim 1, wherein the step of generating at least one connection group comprises:

connecting the nearby three-dimensional blocks according to the distance between the three-dimensional blocks;

selecting a bottommost point as a reference point from a connection between the two connected three-dimensional blocks, and determining whether the connection is conformed to a predetermined connection state according to the reference point, and if the connection is not conformed to the predetermined connection state, then the connection step is repeated; and

collecting the three-dimensional blocks to generate the connection group, wherein the three-dimensional blocks are interconnected and are linked to the reference plane.

10. The method for recognizing three-dimensional control points according to claim 9, wherein in the connection step, two nearest three-dimensional blocks are connected, and if the connection between the two nearest three-dimensional blocks is not conformed to the predetermined connection state, then the two second nearest three-dimensional blocks are selected.

11. A non-transitory computer-readable medium having a plurality of program commands for performing a method for recognizing three-dimensional control points, wherein the method for recognizing three-dimensional control points comprises:

receiving a depth information item corresponding to an image captured by an image capturing apparatus;

generating a plurality of three-dimensional block information items corresponding to a plurality of three-dimensional blocks according to the depth information;

generating at least one reference plane according to the depth information;

generating at least one connection group according to the three-dimensional block information and the reference plane; and

selecting the three-dimensional block nearest to the image capturing apparatus as a control point from the connection group;

wherein the step of generating a plurality of three-dimensional block information items comprises;

detecting a plurality of protrusions according to the depth information;

expanding the protrusions into the three-dimensional block according to the depth differences between the protrusions and the pixels surrounding the protrusions; and

generating the three-dimensional block information items corresponding to the three-dimensional blocks.

12. The non-transitory computer-readable medium according to claim 11, wherein the step of generating a plurality of three-dimensional block information items further comprises:

filtering noise blocks off the three-dimensional blocks according to depth change.

13. The non-transitory computer-readable medium according to claim 11, wherein the step of generating a plurality of three-dimensional block information items further comprises:

determining whether the protrusions are all checked;

if no, then the step of expanding the protrusions into the three-dimensional blocks is repeated.

14. The non-transitory computer-readable medium according to claim 11, wherein the step of generating a plurality of three-dimensional block information items further comprises:

determining a plurality of representative points from the three-dimensional blocks; and

generating the three-dimensional block information items corresponding to the representative points.

15. The non-transitory computer-readable medium, according to claim 14 wherein the representative points respectively are the gravity points of the three-dimensional blocks.

16. The non-transitory computer-readable medium according to claim 11, wherein the step of generating at least one the reference plane comprises:

calculating a statistics of space distribution according to the depth information;

applying interval smoothing and overall weighting to the statistics of space distribution; and

filtering a noise plane off to generate the reference plane.

17. The non-transitory computer-readable medium according to claim 16, wherein the statistics of space distribution is the number of pixels corresponding to different depths.

19. The non-transitory computer-readable medium according to claim 11, wherein the step of generating at least one connection group comprises:

connecting the nearby three-dimensional blocks according to the distance between the three-dimensional blocks;

selecting a bottommost point as a reference point from a connection between the two connected three-dimensional blocks, and determining whether the connection is conformed to the predetermined connection state according to the reference point, and if the connection is not conformed to the predetermined connection state, then the connection step is repeated; and

collecting the three-dimensional blocks to generate the connection group, wherein the three-dimensional blocks are interconnected and are linked to the reference plane.

20. The non-transitory computer-readable medium according to claim 19, wherein in the connection step, two nearest three-dimensional blocks are connected, and if the connection between the two nearest three-dimensional blocks is not conformed to the predetermined connection state, then the two second nearest three-dimensional blocks are selected.

18. A non-transitory computer-readable medium having a plurality of program commands for performing a method for recognizing three-dimensional control points, wherein the method for recognizing three-dimensional control points comprises:

receiving a depth information item corresponding to an image captured by an image capturing apparatus;

generating a plurality of three-dimensional block information items corresponding to a plurality of three-dimensional blocks according to the depth information;

generating at least one reference plane according to the depth information;

generating at least one connection group according to the three-dimensional block information and the reference plane; and

selecting the three-dimensional block nearest to the image capturing apparatus as a control point from the connection group;

calculating a statistics of space distribution according to the depth information;

applying interval smoothing and overall weighting to the statistics of space distribution; and

filtering a noise plane off to generate the reference plane;

wherein in the step of filtering a noise plane off to generate the reference plane, the reference plane is generated according to the highest peak value of the statistics of space distribution.