Method and device for generating a panoramic image

1. A method for generating a panoramic image, comprising:

capturing first and second fisheye images in a first coordinate system by an imaging device, the first coordinate system comprising:

an origin where the imaging device is located;

a Z-axis that points in a first direction toward a rear of the imaging device;

an X-axis that points in a second direction with respect to the imaging device, the Z-axis and the X-axis forming a plane where the imaging device is located; and

a Y-axis that is perpendicular to the plane and points in a third direction with respect to the imaging device;

performing, by at least one processor, a coordinate system rotation process on the first coordinate system, the coordinate system rotation process comprising rotating the first coordinate system around the X-axis by −90°, to generate a second coordinate system;

performing, by the at least one processor, an equirectangular projection process on the first and second fisheye images to respectively obtain first and second equirectangular images in the second coordinate system;

performing, by the at least one processor, a blending process on the first and second equirectangular images to form a blended image; and

performing an orientation correction process on the blended image to obtain the panoramic image.

2. The method of claim 1 , wherein capturing the first and second fisheye images comprises capturing the first and second fisheye images by first and second fisheye cameras of the imaging device, respectively; the first fisheye camera facing toward a negative direction of the Z-axis, and the second fisheye camera facing toward a positive direction of the Z-axis.

3. The method of claim 2 , wherein fields of view of the first and second fisheye cameras are greater than 180 degrees.

4. The method of claim 3 , wherein fields of view of the first and second fisheye cameras are 190 degrees.

5. The method of claim 1 , wherein the equirectangular projection process comprises projecting a fisheye image to an equirectangular image by a first mapping table.

6. The method of claim 5 , wherein the first mapping table comprises positional relations between pixels in the fisheye image and corresponding pixels in the corresponding equirectangular image.

7. The method of claim 6 , wherein the equirectangular projection process further comprises:

receiving coordinates of pixels in the fisheye images;

looking up the received coordinates in the first mapping table;

obtaining from the first mapping table corresponding coordinates of pixels in the corresponding equirectangular images; and

supplying values of pixels in the fisheye images to pixels in the corresponding coordinates of the equirectangular image.

8. The method of claim 1 , wherein the blending process comprises:

identifying feature points in the first equirectangular image which correspond to feature points in the second equirectangular image;

aligning the first and second equirectangular images according to the identified feature points; and

performing a pyramid blending method on the first and equirectangular images to generate the blended image.

9. The method of claim 1 , wherein the orientation correction process comprises projecting pixels of the blended image to the panoramic image according to a second mapping table.

10. The method of claim 9 , wherein the second mapping table comprises positional relations between pixels in the first coordinate system and corresponding pixels in the second coordinate system.

11. A device for generating a panoramic image, comprising:

an imaging device configured to capture first and second fisheye images in a first coordinate system the first coordinate system comprising:

an origin where the imaging device is located;

a Z-axis that points in a first direction toward a rear of the imaging device;

an X-axis that points in a second direction with respect to the imaging device, the Z-axis and the X-axis forming a plane where the imaging device is located; and

a Y-axis that is perpendicular to the plane and points in a third direction with respect to the imaging device;

a memory, configured to store the first and second fisheye images, and instructions; and

at least one processor, configured to execute the instructions to perform:

a coordinate system rotation process on the first coordinate system, the coordinate system rotation process comprising rotating the first coordinate system around the X-axis by −90°, to generate a second coordinate system;

an equirectangular projection process on the first and second fisheye images to obtain first and second equirectangular images in the second coordinate system, respectively;

a blending process on the first and second equirectangular images to form a blended image; and

an orientation correction process on the blended image to obtain the panoramic image.

12. The device of claim 11 , wherein:

the imaging device comprises first and second fisheye cameras to capture the first and second fisheye images, respectively;

the first fisheye camera faces toward a negative direction of the Z-axis; and

the second fisheye camera faces toward a positive direction of the Z-axis.

13. The device of claim 12 , wherein fields of view of the first and second fisheye cameras are greater than 180 degrees.

14. The device of claim 13 , wherein the fields of view of the first and second fisheye cameras are 190 degrees.

15. The device of claim 11 , wherein the equirectangular projection process comprises projecting a fisheye image to an equirectangular image by a first mapping table.

16. The device of claim 15 , wherein the first mapping table comprises positional relations between pixels in the fisheye image and corresponding pixels in the equirectangular image.

17. The device of claim 16 , wherein the equirectangular projection process further comprises:

receiving coordinates of pixels in the fisheye image;

looking up the received coordinates in the first mapping table;

obtaining corresponding coordinates of pixels in the equirectangular image; and

supplying values of the pixels in the fisheye image to pixels in the corresponding coordinates of the equirectangular image.

18. The device of claim 11 , wherein the blending process comprises:

identifying feature points for the first equirectangular image and the second equirectangular image;

aligning the first equirectangular image and the second equirectangular image according to the feature points; and

performing a pyramid blending method on the first equirectangular image and the second equirectangular image to generate the blended image.

19. The device of claim 11 , wherein the orientation correction process comprises projecting pixels of the blended image to the panoramic image according to a second mapping table.

20. The device of claim 19 , the second mapping table comprises positional relations between pixels in the first coordinate system and corresponding pixels in the second coordinate system.