Maximum temperature point tracking method, device and unmanned aerial vehicle

Patent metadata

Field	Value
Publication number	US-11798172-B2
Application number	US-202117503670-A
Country	US
Kind code	B2
Filing date	Oct 18, 2021
Priority date	Nov 30, 2017
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

A method for tracking a maximum temperature point includes acquiring a first pair of coordinates of a maximum temperature point in a current frame of image sensed by an infrared camera, determining a rotation angle of a gimbal equipped with the infrared camera according to the first pair of coordinates of the maximum temperature point in the current frame of image and a pair of coordinates of a target position of the maximum temperature point in a subsequent frame of image, and controlling the gimbal to rotate according to the rotation angle, so as to adjust the maximum temperature point in the subsequent frame of image captured by the infrared camera to be located at the target position.

First claim

What is claimed is:

1. A method for tracking a maximum temperature point, comprising:
acquiring a first pair of coordinates of a maximum temperature point in a current frame of image sensed by an infrared camera;
determining an expected pair of coordinates of the maximum temperature point in a subsequent frame of image to be captured by the infrared camera according to a temperature of the maximum temperature point in the current frame of image and the first pair of coordinates;
determining a rotation angle of a gimbal equipped with the infrared camera according to the expected pair of coordinates of the maximum temperature point in the subsequent frame of image and a pair of coordinates of a target position of the maximum temperature point in the subsequent frame of image; and
controlling the gimbal to rotate according to the rotation angle, so as to adjust the maximum temperature point in the subsequent frame of image captured by the infrared camera to be located at the target position.

2. The method according to claim 1 , further comprising:
obtaining a temperature of the maximum temperature point in the current frame of image.

3. The method according to claim 1 , further comprising, before determining the expected pair of coordinates of the maximum temperature point in the subsequent frame of image to be captured by the infrared camera according to the temperature of the maximum temperature point and the first pair of coordinates:
determining a second pair of coordinates of an expected maximum temperature point in the current frame of image captured by the infrared camera according to visual tracking;
wherein determining the expected pair of coordinates of the maximum temperature point in the subsequent frame of image to be captured by the infrared camera according to the temperature of the maximum temperature point and the first pair of coordinates includes:
determining the expected pair of coordinates of the maximum temperature point in the subsequent frame of image to be captured by the infrared camera according to the temperature of the maximum temperature point, the first pair of coordinates, and the second pair of coordinates of the expected maximum temperature point.

4. The method according to claim 3 , further comprising, before determining the second pair of coordinates of the expected maximum temperature point in the current frame of image captured by the infrared camera according to the visual tracking:
acquiring a bitstream feature at the expected maximum temperature point;
wherein determining the second pair of coordinates of the maximum temperature point in the current frame of image captured by the infrared camera according to the visual tracking includes:
acquiring an infrared bitstream of the current frame of image captured by the infrared camera, and
visually tracking the infrared bitstream according to the bitstream feature to determine the second pair of coordinates.

5. The method according to claim 4 , wherein acquiring the bitstream feature at the expected maximum temperature point includes:
determining the bitstream feature at the expected maximum temperature point according to bitstream features of maximum temperature points corresponding to preceding M expected pairs of coordinates determined in previous M times, wherein M is an integer greater than or equal to 1.

6. The method according to claim 3 , wherein determining the expected pair of coordinates of the maximum temperature point in the subsequent frame of image to be captured by the infrared camera according to the temperature of the maximum temperature point, the first pair of coordinates, and the second pair of coordinates includes, in response to the temperature of the maximum temperature point in the current frame of image sensed by the infrared camera falling within the maximum temperature confidence interval:
determining the expected pair of coordinates according to the first pair of coordinates of the maximum temperature point in the current frame of image and the second pair of coordinates of the expected maximum temperature point in the current frame of image; or
determining the expected pair of coordinates according to the first pair of coordinates of determining the expected pair of coordinates according to the first pair of coordinates of the maximum temperature point in the current frame of image sensed by the infrared camera, the second pair of coordinates of the expected maximum temperature point in the current frame of image, first pairs of coordinates of maximum temperature points in preceding N frames of images before the current frame of image, and second pairs of coordinates of expected maximum temperature points in the N frames of images before the current frame of image,
wherein the preceding N frames of images are consecutive N frames of images in which temperatures of the maximum temperature points fall within the maximum temperature confidence interval, and N is an integer greater than or equal to 1.

7. The method according to claim 1 , wherein determining the expected pair of coordinates of the maximum temperature point in the subsequent frame of image to be captured by the infrared camera according to the temperature of the maximum temperature point and the first pair of coordinates includes, in response to the temperature of the maximum temperature point in the current frame of image falling within a maximum temperature confidence interval:
determining the first pair of coordinates of the maximum temperature point in the current frame of image to be the expected pair of coordinates; or
determining the expected pair of coordinates according to the first pair of coordinates of the maximum temperature point in the current frame of image and first pairs of coordinates of maximum temperature points of preceding N frames of images sensed by the infrared camera before the current frame of image,
wherein the preceding N frames of images are consecutive N frames of images in which temperatures of the maximum temperature points fall within the maximum temperature confidence interval, and N is an integer greater than or equal to 1.

8. The method according to claim 7 , further comprising:
in response to the temperature of the maximum temperature point in the current frame of image not falling within the maximum temperature confidence interval, determining an expected pair of coordinates determined in a preceding frame of image to be the expected pair of coordinates.

9. The method according to claim 7 , wherein the temperature of the maximum temperature point in the current frame of image sensed by the infrared camera is determined as falling within the maximum temperature confidence interval in response to:
a variance or standard deviation between the temperature of the maximum temperature point in the current frame of image and temperatures of maximum temperature points in preceding K frames of images before the current frame being less than a preset value,
wherein the preceding K frames of images are continuous consecutive K frames of images in which temperatures of the maximum temperature points fall within the maximum temperature confidence interval, and K is an integer greater than or equal to 1.

10. The method according to claim 7 , wherein determining the expected pair of coordinates according to the first pair of coordinates of the maximum temperature point in the current frame of image and the first pairs of coordinates of the maximum temperature points of the preceding N frames of images includes:
performing an operation of a least squares method on the first pair of coordinates of the maximum temperature point in the current frame of image and the first pairs of coordinates of the ma

Assignees

• Sz Dji Technology Co Ltd

Inventors

• Weng Chao
• Wang Mingxi
• Zhang Wei

Classifications

• G01J5/00

  Radiation pyrometry, e.g. infrared or optical thermometry · CPC title

• H04N23/23

  from thermal infrared radiation · CPC title

• G06T7/246 Primary

  using feature-based methods, e.g. the tracking of corners or segments · CPC title

• G06V10/143

  Sensing or illuminating at different wavelengths · CPC title

• G06V20/176

  Urban or other man-made structures · CPC title