TOF (Time of Flight)-based optical flow positioning system

Abstract

The invention relates to the field of indoor visual positioning and navigation and in particular relates to a TOF (Time of Flight)-based optical flow positioning system. The system comprises an image and inertia data acquisition module, an optical flow calculation module, a depth estimation module, a motion estimation module and an output module. According to the system disclosed by the invention, the image information as well as acceleration and angular velocity are acquired by the image and inertia data acquisition module, characteristic point information and depth estimation information of the image can be acquired by the optical flow calculation module and the depth estimation module, and then the motion estimation module combines the characteristic point information and depth estimation information and calculates to obtain the final positioning position, so that accurate and rapid three-dimensional positioning is realized.

Description

technical field [0001] The invention relates to the field of indoor visual positioning and navigation, in particular to a TOF-based optical flow positioning system. Background technique [0002] Optical flow positioning is the main positioning method for drones flying indoors. When in use, a camera is usually installed downwards on the bottom of the drone, and the movement of the camera itself is estimated by calculating the movement of pixels in the image, and then passed Calculate the optical flow to get the speed of the camera itself and perform positioning. Most of the current optical flow positioning schemes use a camera and an ultrasonic ranging module, and use the SAD algorithm to calculate the optical flow. This optical flow positioning scheme has the following defects: [0003] 1. The distance measurement accuracy of the ultrasonic ranging module is low, and it is easily disturbed by the external environment such as temperature and wind speed. When the road is roug...

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Problems solved by technology

[0003] 1. The distance measurement accuracy of the ultrasonic ranging module is low, and it is easily disturbed by the external environment such as temperature and wind speed. When the road is rough and the altitude changes rapidly, the ultrasonic ranging can only feedback the height of the central area. The distance measurement accuracy is poor, and the deviation is serious when applied to sound-absorbing materials, resulting in inaccurate optical flow positioning;

[0004] 2. Optical flow calculations mostly use dense optical flow calculations. In order to achieve real-time effects, usually only the optical flow in a small area in the center can be calculated, and the calculated optical flow results and the depth measured by ultrasonic waves are used directly for motion estimation. The collected samples are too large. Less, ignoring the fact that the depth of some areas in the image block does not match the optical flow, it is easy to generate cumulative errors, resulting in drift

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