面向交通事故现场三维实景建模的无人机航拍参数

Key parameters of UAV photography for 3D real scene reconstruction of traffic accident site

在交通事故现场三维实景建模的图像采集过程中,针对无人机(UAV)航拍参数主要依靠人工经验设置,导致模型测量误差大、精度低的问题,提出一种无人机航拍关键参数自动计算方法。首先,确认单镜头无人机环绕事故现场航拍的关键参数为航拍高度、云台角度和拍摄间隔角,并分析其与成像范围、成像精度以及重叠度的数值关系;然后,构建无人机航拍关键参数计算模型,以给定事故现场场景、无人机技术参数、图像长宽比以及重叠度要求为输入,在事故现场处于有效成像范围且无成像盲区的前提下,以提高图像利用率保障模型精度和呈现效果为目标,自动计算得到航拍参数;最后,结合实例,应用该方法计算无人机航拍参数完成事故现场的图像采集,经测算,构建的事故现场三维实景模型的平均测量误差为1.72%,测量精度为3.54 cm,相较于人工经验法平均误差降低47.56%,精度提高48.40%。研究表明:该方法能实现交通事故现场三维实景建模的航拍参数自动计算,构建厘米级误差的三维实景模型,可提升无人机航拍的参数化和自动化水平。

Aiming at the problem of UAV aerial photography parameters relying on manual experience when collecting image of 3D real scene reconstruction at traffic accident sites,which led to large model measurement errors and low precision,an automatic calculation method of key parameters of UAV aerial photography was proposed.First,the key parameters of aerial photography used by single-lens UAV for images acquisition of traffic accident site were altitude,gimbal angle and shooting interval angle.The numerical relationships of the key parameters with the imaging range,imaging accuracy and overlap rate were analyzed.Then,the aerial photography key parameters computation model was constructed.The key input parameters were the given accident site,UAV technical parameters,image aspect ratio and overlap requirements.On the premise that the accident site was in the effective imaging range and there was no imaging blind zone,the UAV photography parameters were automatically calculated with the goal of improving the accuracy and presentation effect of the image utilization rate model.Finally,combined with case application,the UAV aerial photography parameters calculated by this method were applied to complete the image acquisition at the accident sites,and the constructed 3D real scene model could clearly and completely present the overview of the accident site,with an average measurement error of 1.72%,and a measurement accuracy of 3.54 cm.Compared with the manual empirical method,the average error of the method was reduced by 47.56%,and the accuracy was improved by 48.40%.The study shows that this method can realize the automatic quantitative calculation of aerial photography parameters for 3D real scene reconstruction of traffic accident sites,construct the model with centimeter-level error,and improve the parameterization and automation of UAV aerial photography.