US Patent No. 10,515,271

FLIGHT DEVICE AND FLIGHT CONTROL METHOD


Patent No. 10,515,271
Issue Date December 24, 2019
Title Flight Device And Flight Control Method
Inventorship Zuoguang Li, Guangdong (CN)
Assignee AUTEL ROBOTICS CO., LTD., Shenzhen (CN)

Claim of US Patent No. 10,515,271

1. A flight device, comprisinga processor; and
a memory communicatively connected with the processor, the memory storing instructions, wherein when executing the instructions, the processor is configured to:
acquire an image captured by a camera module of the flight device;
acquire a height of the flight device sensed by a distance sensor of the flight device;
determine a scene in which the flight device is located according to at least one parameter of the image captured by the camera module;
analyze changes in the parameters of the two adjacent image frames according to an algorithm corresponding to the scene in which the flight device is located so as to calculate an image X-offset and an image Y-offset of a second image frame of the two adjacent image frames relative to a first image frame of the two adjacent image frames;
acquire acceleration and angular velocity of the flight device in three dimensions that are detected by an acceleration sensor of the flight device;
compensate for the image X-offset and the image Y-offset according to the acceleration and the angular velocity of the flight device to obtain image correction offsets comprising a corrected image X-offset and a corrected image Y-offset;
calculate an X-offset and a Y-offset in world coordinates corresponding to the image correction offsets according to a lens focal length of the camera module, a height of the flight device and the image correction offsets; and
derive a velocity of the flight device according to a time interval between time points at which the two adjacent image frames are captured and according to the X-offset and the Y-offset in world coordinates;
wherein the at least one parameter comprises texture, and the processor is further configured to:
process the image by use of the sobel gradient algorithm to obtain a gradient matrix;
count the number of pixels of which the gradient is greater than a predetermined first threshold in the gradient matrix;
determine that the current scene is a richly textured scene if the number as counted is greater than a second threshold;
determine that the texture is relatively poor and that the current scene is a relatively poorly textured scene if the number as counted is smaller than or equal to the second threshold;
adopt the algorithm of gray template matching when the current scene is a richly textured scene, to analyze changes in the parameters of the two adjacent image frames, so as to calculate the image X-offset and the image Y-offset of the second image frame of the two adjacent image frames relative to the first image frame of the two adjacent image frames; and
adopt the algorithm of sobel gradient template matching when the current scene is a relative poorly textured scene, to analyze changes in the parameters of the two adjacent image frames, so as to calculate the image X-offset and the image Y-offset of the second image frame of the two adjacent image frames relative to the first image frame of the two adjacent image frames.