UAV Placement for Real-time Video Acquisition: A Tradeoff between Resolution and Delay

TL;DR

This paper introduces an oblique UAV photography model and an optimized placement scheme to reduce transmission delay while maintaining image resolution in real-time video acquisition.

Contribution

It proposes a novel oblique photography model and an optimization framework for UAV placement to minimize delay, improving over traditional vertical photography methods.

Findings

The oblique model reduces transmission delay significantly.

The optimization scheme effectively balances resolution and delay.

Numerical results demonstrate substantial delay savings.

Abstract

Recently, UAVs endowed with high mobility, low cost, and remote control have promoted the development of UAV-assisted real-time video/image acquisition applications, which have a high demand for both transmission rate and image resolution. However, in conventional vertical photography model, the UAV should fly to the top of ground targets (GTs) to capture images, thus enlarge the transmission delay. In this paper, we propose an oblique photography model, which allows the UAV to capture images of GTs from a far distance while still satisfying the predetermined resolution requirement. Based on the proposed oblique photography model, we further study the UAV placement problem in the cellular-connected UAV-assisted image acquisition system, which aims at minimizing the data transmission delay under the condition of satisfying the predetermined image resolution requirement. Firstly, the proposed scheme is first formulated as an intractable non-convex optimization problem. Then, the original problem is simplified to obtain a tractable suboptimal solution with the help of the block coordinate descent and the successive convex approximation techniques. Finally, the numerical results are presented to show the effectiveness of the proposed scheme. The numerical results have shown that the proposed scheme can largely save the transmission time as compared to the conventional vertical photography model.