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Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles.

Huang KL, Chiu CC, Chiu SY, Teng YJ, Hao SS - Sensors (Basel) (2015)

Bottom Line: The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images.A forward-looking camera is mounted on the upside of the aircraft's nose.Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33551, Taiwan. 1040510304@ndu.edu.tw.

ABSTRACT
The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs) has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft's nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft's nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

No MeSH data available.


Different detection results under various terrains.
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sensors-15-16848-f008: Different detection results under various terrains.

Mentions: On the left of Figure 7, the valid flying direction, i.e., the same angle as θmax = 72°, is marked as green arrows. There are 29 such motion vectors. The other motion vectors are marked as light green arrows. From the detection results, it is obvious that the proposed flying direction detection algorithm is suitable for detecting the motion between consecutive images. The valid flying direction of 72° indicates that the influence of the wind is pushing the UAV to the right by 18°. The magnitude of the motion vector is the disparity of the stereo vision. The larger the magnitude of the motion vector, the closer the ground is to the UAV. Therefore, the smallest magnitude motion vectors signify the distance between the UAV and the ground, rather than buildings or trees. Figure 8 illustrates different detection results for various terrains.


Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles.

Huang KL, Chiu CC, Chiu SY, Teng YJ, Hao SS - Sensors (Basel) (2015)

Different detection results under various terrains.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541911&req=5

sensors-15-16848-f008: Different detection results under various terrains.
Mentions: On the left of Figure 7, the valid flying direction, i.e., the same angle as θmax = 72°, is marked as green arrows. There are 29 such motion vectors. The other motion vectors are marked as light green arrows. From the detection results, it is obvious that the proposed flying direction detection algorithm is suitable for detecting the motion between consecutive images. The valid flying direction of 72° indicates that the influence of the wind is pushing the UAV to the right by 18°. The magnitude of the motion vector is the disparity of the stereo vision. The larger the magnitude of the motion vector, the closer the ground is to the UAV. Therefore, the smallest magnitude motion vectors signify the distance between the UAV and the ground, rather than buildings or trees. Figure 8 illustrates different detection results for various terrains.

Bottom Line: The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images.A forward-looking camera is mounted on the upside of the aircraft's nose.Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33551, Taiwan. 1040510304@ndu.edu.tw.

ABSTRACT
The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs) has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft's nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft's nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

No MeSH data available.