Epstein Brandon, Westlake Bryce Garreth
Middlesex County Prosecutor's Office, 25 Kirkpatrick Street, 3rd Floor, New Brunswick, NJ, 08901.
Department of Justice Studies, San Jose State University, San Jose, CA, 95192.
J Forensic Sci. 2019 Sep;64(5):1523-1529. doi: 10.1111/1556-4029.14053. Epub 2019 Mar 28.
The prevalence of security and in-car video has increased the number of motor vehicle accidents captured on digital video. However, inconsistencies in how to accurately determine time and distance for vehicle speed has led to examinations with varying results. A potential solution for calculating time intervals is to use frame timing contained within many digital video file's metadata, recorded with 0.000001 sec precision. This paper examines a fatal motor vehicle accident where frame timing information was used with distance measurements from reverse projection photogrammetry to calculate vehicle speed. A margin of error was then calculated based on the accuracy in performing reverse projection photogrammetry distance measurements. The resulting speed calculation was then compared to event data recorder data and found to be within an average of ±1.43538 MPH. Using specific time intervals may lead investigators to more accurate speed calculations, specifically those involving variable frame rate video.
行车安全摄像头和车内视频的普及增加了数字视频捕捉到的机动车事故数量。然而，在如何准确确定车速的时间和距离方面存在不一致，导致检测结果各异。计算时间间隔的一个潜在解决方案是使用许多数字视频文件元数据中包含的帧定时，其记录精度为0.000001秒。本文研究了一起致命机动车事故，其中帧定时信息与反向投影摄影测量法的距离测量值一起用于计算车速。然后根据执行反向投影摄影测量距离的精度计算误差范围。然后将所得的速度计算结果与事件数据记录器数据进行比较，发现平均误差在±1.43538英里/小时以内。使用特定的时间间隔可能会使调查人员得出更准确的速度计算结果，特别是对于那些涉及可变帧率视频的情况。
