Projecting apparatus and projecting calibration method

1. A projecting apparatus, comprising:

a projecting device, configured to project a reversible structured light code onto a surface;

an image-capturing device, configured to capture the reversible structured light code projected onto the surface and obtain image data; and

a processing device, coupled to the projecting device and the image-capturing device, and configured to receive the image data, generate three-dimensional point cloud information by performing decoding on the image data, and obtain scanning shift information corresponding to the projecting device according to the three-dimensional point cloud information, three-dimensional information corresponding to the surface, a plurality of pieces of compensation depth information, and a projection distance;

wherein the processing device is further configured to obtain depth error information by performing computation according to the three-dimensional point cloud information and three-dimensional information corresponding to the surface, obtain projecting error information by performing computation according to the depth error information, the three-dimensional point cloud information and the plurality of pieces of compensation depth information, and obtain the scanning shift information by performing computation according to the projecting error information and the projection distance.

2. The projecting apparatus as claimed in claim 1 , wherein the scanning shift information is computed based on the following equation:

θ

(

x

,

y

)

=

tan

-

1

⁢

d

(

x

,

y

)

h

,

wherein θ( x,y ) is the scanning shift information, d (x,y) is the projecting error information, and h is the projection distance.

3. The projecting apparatus as claimed in claim 1 , wherein the processing device is further configured to obtain the pieces of compensation depth information by performing computation according to a plurality of pixel shift quantities.

4. The projecting apparatus as claimed in claim 3 , wherein the processing device is further configured to compute a plurality of compensation depth differences between the three-dimensional point cloud information and the pieces of compensation depth information, select one of the pixel shift quantities corresponding to a smallest difference of differences between the depth error information and the compensation depth differences, and compute the projecting error information according to the selected pixel shift quantity.

5. The projecting apparatus as claimed in claim 4 , wherein the projecting error information is computed based on the following equation:

Δ d (x,y) =( i,j )× Pd,

wherein Δd (x,y) is the projecting error information, (i,j) are the pixel shift quantities, and Pd is a transformation ratio between a pixel and a length.

6. The projecting apparatus as claimed in claim 1 , wherein the reversible structured light code is a gray stripe light code.

7. The projecting apparatus as claimed in claim 1 , wherein the projecting device is a micro electro mechanical systems scanning mirror projector.

8. The projecting apparatus as claimed in claim 1 , wherein the surface is a surface of a standard part.

9. The projecting apparatus as claimed in claim 1 , wherein the processing device further calibrates the projecting device according to the scanning shift information.

10. A projecting calibration method, comprising:

projecting a reversible structured light code onto a surface by a projecting device;

capturing the reversible structured light code projected onto the surface and obtaining image data by an image-capturing device; and

receiving the image data, generating three-dimensional point cloud information by performing decoding on the image data, and obtaining scanning shift information corresponding to the projecting device according to the three-dimensional point cloud information, three-dimensional information corresponding to the surface, a plurality of pieces of compensation depth information, and a projection distance by a processing device;

wherein the step of receiving the image data, generating the three-dimensional point cloud information by performing decoding on the image data, and obtaining the scanning shift information corresponding to the projecting device according to the three-dimensional point cloud information and three-dimensional information corresponding to the surface by the processing device further comprises:

obtaining depth error information by performing computation according to the three-dimensional point cloud information and three-dimensional information corresponding to the surface;

obtaining projecting error information by performing computation according to the depth error information, the three-dimensional point cloud information and the plurality of pieces of compensation depth information; and

obtaining the scanning shift information by performing computation according to the projecting error information and the projection distance.

11. The projecting calibration method as claimed in claim 10 , wherein the scanning shift information is computed based on the following equation:

θ

(

x

,

y

)

=

tan

-

1

⁢

d

(

x

,

y

)

h

wherein θ (x,y) is the scanning shift information, d (x,y) is the projecting error information, and h is the projection distance.

12. The projecting calibration method as claimed in claim 10 , wherein the step of receiving the image data, generating the three-dimensional point cloud information by performing decoding on the image data, and obtaining the scanning shift information corresponding to the projecting device according to the three-dimensional point cloud information and three-dimensional information corresponding to the surface by the processing device further comprises:

obtaining the pieces of compensation depth information by performing computation according to a plurality of pixel shift quantities by the processing device.

13. The projecting calibration method as claimed in claim 12 , wherein the step of obtaining projecting error information by performing computation according to the depth error information, the three-dimensional point cloud information and the pieces of compensation depth information comprises:

computing a plurality of compensation depth differences between the three-dimensional point cloud information and the pieces of compensation depth information by the processing device; and

selecting one of the pixel shift quantities corresponding to a smallest difference of differences between the depth error information and the compensation depth differences by the processing device, and computing the projecting error information according to the selected pixel shift quantity by the processing device.

14. The projecting calibration method as claimed in claim 13 , wherein the projecting error information is computed based on the following equation:

Δ d (x,y) =( i,j )× Pd,

wherein Δd (x,y) is the projecting error information, (i,j) are the pixel shift quantities, and Pd is a transformation ratio between a pixel and a length.

15. The projecting calibration method as claimed in claim 10 , wherein the reversible structured light code is a gray stripe light code.

16. The projecting calibration method as claimed in claim 10 , wherein the projecting device is a micro electro mechanical systems scanning mirror projector.

17. The projecting calibration method as claimed in claim 10 , wherein the surface is a surface of a standard part.

18. The projecting calibration method as claimed in claim 10 , further comprising:

calibrating the projecting device according to the scanning shift information.