SCIENTIA SINICA Informationis, Volume 50 , Issue 5 : 692-703(2020) https://doi.org/10.1360/N112019-00034

## Obstacle visual sensing based on deep learning for low-altitude small unmanned aerial vehicles

• AcceptedMay 5, 2019
• PublishedApr 16, 2020
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### Abstract

An obstacle real-time sensing method, which is based on deep learning and target tracking method and integrated with monocular vision and binocular vision, is proposed for unmanned aerial vehicles (UAVs) in this paper. Firstly, it uses the deep learning method to detect and recognize the first-frame figure collected by cameras. Then, it uses the target tracking algorithm to track the detection results for the first-frame figure in real time to improve the real-time performance of the detection system. Meanwhile, it uses the binocular vision technology to execute the three-dimensional reconstruction for the current frame of the entire figure to obtain the environmental spatial information. Subsequently, combined with the points clustering strategy and the information fusion method, it can resolve the types, spatial locations, and outlines of obstacles. Finally, to verify the proposed method, we developed a physical prototype, and the results showed that the real-time sensing for obstacles can be realized under the condition that UAVs are equipped with one binocular camera.

### References

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• Figure 1

Block diagram of the vision-based real-time obstacle perception method

• Figure 2

(Color online) Samples in the data set

• Figure 3

(Color online) Target detection and recognition results using YOLOv2

• Figure 4

(Color online) 3D reconstruction based on binocular stereo vision

• Figure 5

Obstacle extraction using information fusion method

• Figure 6

Perception of the physical prototype. (a) Real-time detection result using YOLOv2 and KCF tracking algorithm; (b) point cloud for 3D environment reconstruction using binocular stereo vision

• Figure 7

(Color online) Detection and tracking results for the physical object using the proposed algorithm. (a) Image at the 1st frame; (b) image at the 60th frame; (c) image at the 120th frame

• Table 1   Perception results of the physical prototype in indoor environments
 Center coordinate $X$ (m) Center coordinate $Y$ (m) Center coordinate $Z$ (m) Width (m) Height (m) Group 1 Real value 0.000 0.000 1.500 0.370 0.370 Measured value $-$0.012 0.021 1.493 0.374 0.374 Error $-$0.012 0.021 $-$0.007 0.004 0.004 Group 2 Real value 0.000 0.400 1.980 0.370 0.370 Measured value 0.009 0.443 1.981 0.374 0.374 Error 0.009 0.043 0.001 0.004 0.004 Group 3 Real value $-$0.400 0.400 2.500 0.370 0.370 Measured value $-$0.378 0.433 2.550 0.374 0.382 Error 0.022 0.033 0.050 0.004 0.012 Group 4 Real value $-$0.400 0.400 3.000 0.370 0.370 Measured value $-$0.447 0.447 2.987 0.402 0.382 Error $-$0.047 0.047 0.013 0.032 0.012 Group 5 Real value 0.000 0.400 4.000 0.370 0.370 Measured value 0.037 0.442 3.951 0.397 0.420 Error 0.037 0.042 0.049 0.027 0.050
• Table 2   Statistical results of position error mean values and standard deviations$^{\rm~a)}$
 $X$-EM (cm) $X$-SD (cm) $Y$-EM (cm) $Y$-SD (cm) $Z$-EM (cm) $Z$-SD (cm) Group 1 1.4 0.5 1.5 0.4 1.1 0.3 Group 2 1.4 0.4 1.3 0.4 1.1 0.4 Group 3 1.8 0.6 2.2 0.4 2.2 0.1 Group 4 2.3 0.6 3.2 1.0 3.8 0.5 Group 5 2.6 0.6 2.8 0.6 5.4 0.9

a$X/Y/Z$-EM represents $X/Y/Z$-axis position error mean value and $X/Y/Z$-SD represents $X/Y/Z$-axis standard deviation.

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