Parameter calibration method and apparatus

Patent metadata

Field	Value
Publication number	US-12307715-B2
Application number	US-202217854506-A
Country	US
Kind code	B2
Filing date	Jun 30, 2022
Priority date	Dec 30, 2019
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

This application provides a parameter calibration method and apparatus, which may be applied to calibration of an intrinsic parameter and an extrinsic parameter of an image shooting device. According to the method and apparatus, with a position of a calibration pattern fixed, a position and an angle of the image shooting device relative to the calibration pattern are accurately adjusted by changing a pose parameter of the image shooting device, so that the image shooting device photographs the calibration pattern at each given position and angle relative to the calibration pattern, to obtain at least one shooting result. The shooting result can correspond to coordinate in a pixel coordinate system and a world coordinate system, so that accuracy of an intrinsic parameter and an extrinsic parameter is correspondingly calculated.

First claim

What is claimed is:

1. A parameter calibration method, comprising:
generating a first calibration pattern for calibrating an image shooting device;
sending a first instruction, wherein the first instruction indicates a group of pose parameters of the image shooting device in a first time period, and wherein the group of pose parameters indicates a pose of the image shooting device;
sending a second instruction to the image shooting device, wherein the second instruction indicates a shooting occasion, a quantity of shooting times, or the shooting occasion and the quantity of shooting times of the image shooting device in the first time period;
obtaining, from the image shooting device, a shooting result resulting from a shot that is based on the first instruction and the second instruction, wherein the shooting result comprises at least a portion of the first calibration pattern;
extracting a quantity of feature points from the shooting result that correspond to a field of view of the image shooting device;
determining at least one sub-area comprised in the first calibration pattern;
performing uniformity adjustment on the quantity of feature points in the at least one sub-area; and
determining at least one intrinsic parameter of the image shooting device based on the shooting result.

2. The method according to claim 1 , wherein sending the first instruction comprises:
sending the first instruction to a motion mechanism, wherein the motion mechanism carries the image shooting device, and wherein the group of pose parameters is used by the motion mechanism to control the pose of the image shooting device.

3. The method of claim 1 , wherein the shooting result comprises at least one image from the image shooting device captured in response to the second instruction, and wherein the image comprises a photo or a video.

4. The method of claim 1 , further comprising:
determining that a repetition precision of a first parameter in the at least one intrinsic parameter is greater than a corresponding error threshold; and
adjusting at least one of the first calibration pattern to a second calibration pattern or an image quality of the first calibration pattern.

5. The method of claim 4 , wherein at least one of quantities or sizes of markers in the first calibration pattern and the second calibration pattern are different.

6. The method of claim 1 , wherein the first calibration pattern is a preset grayscale pattern, and wherein the at least one intrinsic parameter comprises a white balance parameter of the image shooting device.

7. The method of claim 1 , wherein the first calibration pattern is a preset monochrome pattern, and wherein the at least one intrinsic parameter comprises a halo parameter of the image shooting device.

8. The method of claim 1 , wherein the first calibration pattern is a preset color card pattern comprising a plurality of standard colors, and wherein the at least one intrinsic parameter comprises a chromatic aberration parameter of the image shooting device.

9. The method of claim 1 , wherein the first calibration pattern is a preset calibration board pattern comprising lines of different angles, and wherein the at least one intrinsic parameter comprises a modulation transfer function parameter of the image shooting device.

10. An apparatus comprising:
a processor configured to execute computer instructions to cause the apparatus to:
generate a first calibration pattern for calibrating an image shooting device;
send a first instruction, wherein the first instruction indicates a group of pose parameters of the image shooting device in a first time period, and wherein the group of pose parameters indicates a pose of the image shooting device;
send a second instruction to the image shooting device, wherein the second instruction indicates a shooting occasion, a quantity of shooting times, or the shooting occasion and the quantity of shooting times of the image shooting device in the first time period;
obtain a shooting result, that is shot according to the first instruction and the second instruction, from the image shooting device, wherein the shooting result comprises at least a portion of the first calibration pattern;
extract a quantity of feature points from the shooting result that correspond to a field of view of the image shooting device;
determine at least one sub-area comprised in the first calibration pattern;
perform uniformity adjustment on the quantity of feature points in the at least one sub-area; and
determine at least one intrinsic parameter of the image shooting device based on the shooting result.

11. The apparatus of claim 10 , wherein when the processor executes the computer instructions, the apparatus is enabled to perform:
sending the first instruction to a motion mechanism, wherein the motion mechanism carries the image shooting device, and wherein the group of pose parameters is used by the motion mechanism to control the pose of the image shooting device.

12. The apparatus of claim 10 , wherein the shooting result comprises at least one image from the image shooting device captured in response to the second instruction, wherein the image comprises at a photo or a video.

13. The apparatus of claim 10 , wherein the processor is further configured to execute the computer instructions to cause the apparatus to:
determine that a repetition precision of a first parameter in the at least one intrinsic parameter is greater than a corresponding error threshold; and
adjust at least one of the first calibration pattern to a second calibration pattern or an image quality of the first calibration pattern.

14. The apparatus of claim 13 , wherein at least one of quantities and sizes of markers in the first calibration pattern and the second calibration pattern are different.

15. The apparatus of claim 10 , wherein the first calibration pattern is a preset grayscale pattern, and the at least one intrinsic parameter comprises a white balance parameter of the image shooting device.

16. The apparatus of claim 10 , wherein the first calibration pattern is a preset monochrome pattern, and the at least one intrinsic parameter comprises a halo parameter of the image shooting device.

17. The apparatus of claim 10 , wherein the first calibration pattern is a preset color card pattern comprising a plurality of standard colors, and the at least one intrinsic parameter comprises a chromatic aberration parameter of the image shooting device.

18. The apparatus of claim 10 , wherein the first calibration pattern is a preset calibration board pattern comprising lines of different angles, and the at least one intrinsic parameter comprises a modulation transfer function parameter of the image shooting device.

19. A parameter calibration system comprising:
a control device configured to:
generate a first calibration pattern for calibrating an image shooting device;
send a first instruction to a motion mechanism, wherein the first instruction indicates a group of pose parameters of the image shooting device in a first time period;
send a second instruction to the image shooting device, wherein the second instruction indicates at least one of a shooting occasion and a quantity of shooting times of the image shooting device in the first time period;
obtain shooting result, that is shot according to the first instruction and the second instruction, from the image shooting device, wherein the shooting result comprises at least a portion of the first calibration pattern;
extract a quantity of feature poin

Assignees

• Shenzhen Yinwang Intelligent Technology Co Ltd

Inventors

• Chen Yilun
• Li Han

Classifications

• G06T7/73

  using feature-based methods · CPC title

• G06T7/80 Primary

  Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration · CPC title