Virtual lens simulation for video and photo cropping

Patent metadata

Field	Value
Publication number	US-11164282-B2
Application number	US-202017075943-A
Country	US
Kind code	B2
Filing date	Oct 21, 2020
Priority date	May 20, 2015
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

In a video capture system, a virtual lens is simulated when applying a crop or zoom effect to an input video. An input video frame is received from the input video that has a first field of view and an input lens distortion caused by a lens used to capture the input video frame. A selection of a sub-frame representing a portion of the input video frame is obtained that has a second field of view smaller than the first field of view. The sub-frame is processed to remap the input lens distortion to a desired lens distortion in the sub-frame. The processed sub-frame is the outputted.

First claim

The invention claimed is:

1. A system for simulating image distortion of a virtual lens in a video, the system comprising:
one or more processors; and
a non-transitory computer-readable storage medium storing instructions that when executed cause the one or more processors to perform steps including:
accessing input images, the input images including fields of view of a scene, the input images depicting the scene with an input lens distortion centered in the fields of view based on lens characteristics of a lens through which the input images are captured, wherein the lens characteristics of the lens cause straight lines in the scene to appear as curved lines in at least a portion of the input images or cause lines of same length to appear as lines of different lengths in different portions of the input images;
selecting reduced fields of view of the scene smaller than the fields of view of the input images, the reduced fields of view including lens distortion effects as a function of the input lens distortion present in the fields of view of the input images, positions of the reduced fields of view within the fields of view of the input images, and size of the reduced fields of view; and
generating output images based on the lens distortion effects in the reduced fields of view and a desired lens distortion, the output images including portions of the input images within the reduced fields of view, the desired lens distortion being consistent with the lens characteristics of the lens, wherein generation of the output images includes remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view to transform the lens distortion effects present in the reduced fields of view to the desired lens distortion such that portions of the scene depicted in the output images appear to have been captured using the reduced fields of view.

2. The system of claim 1 , wherein image stabilization is applied to the input images.

3. The system of claim 1 , wherein the reduced fields of view are selected based on metadata associated with the input images.

4. The system of claim 3 , wherein the metadata indicates motion or orientation of a camera that captured the input images.

5. The system of claim 4 , wherein the metadata comprises velocity vectors and/or acceleration vectors representative of the motion of the camera that captured the input images.

6. The system of claim 1 , wherein the output images are used as video frames of an output video, and remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view results in the output video having consistent frame-to-frame lens characteristics.

7. The system of claim 6 , wherein the reduced fields of view are selected in post-processing after capture of the input images, the selection of the reduced fields of view in the post-processing performed using a post-processing tool.

8. The system of claim 6 , wherein the reduced fields of view are selected during capture of the input images.

9. The system of claim 1 , wherein remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view is performed via a direct transformation that describes a relationship between the input lens distortion centered in the fields of view of the input images and the desired lens distortion centered in the reduced fields of view.

10. The system of claim 1 , wherein remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view is performed via a two-step transformation that removes the input lens distortion centered in the fields of view of the input images and applies the desired lens distortion centered in the reduced fields of view.

11. A method for simulating image distortion of a virtual lens in a video, the method comprising:
accessing input images, the input images including fields of view of a scene, the input images depicting the scene with an input lens distortion centered in the fields of view based on lens characteristics of a lens through which the input images are captured, wherein the lens characteristics of the lens cause straight lines in the scene to appear as curved lines in at least a portion of the input images or cause lines of same length to appear as lines of different lengths in different portions of the input images;
selecting reduced fields of view of the scene smaller than the fields of view of the input images, the reduced fields of view including lens distortion effects as a function of the input lens distortion present in the fields of view of the input images, positions of the reduced fields of view within the fields of view of the input images, and size of the reduced fields of view; and
generating output images based on the lens distortion effects in the reduced fields of view and a desired lens distortion, the output images including portions of the input images within the reduced fields of view, the desired lens distortion being consistent with the lens characteristics of the lens, wherein generation of the output images includes remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view to transform the lens distortion effects present in the reduced fields of view to the desired lens distortion such that portions of the scene depicted in the output images appear to have been captured using the reduced fields of view.

12. The method of claim 11 , wherein image stabilization is applied to the input images.

13. The method of claim 11 , wherein the reduced fields of view are selected based on metadata associated with the input images.

14. The method of claim 13 , wherein the metadata indicates motion or orientation of a camera that captured the input images.

15. The method of claim 14 , wherein the metadata comprises velocity vectors and/or acceleration vectors representative of the motion of the camera that captured the input images.

16. The method of claim 11 , wherein the output images are used as video frames of an output video, and remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view results in the output video having consistent frame-to-frame lens characteristics.

17. The method of claim 16 , wherein the reduced fields of view are selected in post-processing after capture of the input images, the selection of the reduced fields of view in the post-processing performed using a post-processing tool.

18. The method of claim 16 , wherein the reduced fields of view are selected during capture of the input images.

19. The method of claim 11 , wherein remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the reduced fields of view is performed via a direct transformation that describes a relationship between the input lens distortion centered in the fields of view of the input images and the desired lens distortion centered in the reduced fields of view.

20. The method of claim 11 , wherein remapping of the input lens distortion centered in the fields of view of the input images to the desired lens distortion centered in the re

Assignees

• Gopro Inc

Inventors

• Newman David A
• Bodinet Joshua Edward
• Sievert Otto Kenneth
• Macmillan Timothy

Classifications

• G06T2207/10004

  Still image; Photographic image · CPC title

• G06T3/00

  Geometric image transformations in the plane of the image · CPC title

• G06T3/40

  Scaling of whole images or parts thereof, e.g. expanding or contracting · CPC title

• G06T2207/20021

  Dividing image into blocks, subimages or windows · CPC title

• G06T2210/22

  Cropping · CPC title