Forensics & Accident Recon. Articles

The purpose of this study was to compare the accuracy and precision between the Reverse Projection and PhotoModeler methods for suspect height analysis. Thirty analysts were assigned to measure the heights of three different suspects, one for each method, with the suspects having been recorded standing at three different distances in a scene. Reverse Projection yielded a greater range of error and tended to have higher standard deviations than PhotoModeler, but the overall accuracy between the two methods was found to be comparable. The majority of absolute measurement errors for both methods were less than 2 cm.

The purpose of this study was to examine how camera resolution and suspect-camera distance affect the accuracy and precision of suspect height estimations using PhotoModeler software. Interaction plots demonstrated little difference in errors for most resolutions and positions. The accuracy and precision of height estimates began to decrease with resolutions under 960H and distances over 36.5 m.

Mr. Mayda, a long-time user of PhotoModeler, explains how photogrammetry, and animation based on that photogrammetric modeling, is being used in forensics.

PhotoModeler can solve important information about the single camera and the scene at the time of the crime, by using the image captured at the time of the crime, and combining that with 3D data captured after the crime.

In this paper a detailed method is described using PhotoModeler to ‘marry’ the detail of a 3D laser scan with one still from a security camera, and then exported to 3D Studio Max for further analysis.

Three vehicles of varying size were measured using an optimized, practical photogrammetry technique and the results were
compared to measurements acquired via total station and a FaroArm. This research shows photogrammetry can be highly
accurate and efficient with proper methodology, while also expanding on the photogrammetry literature database and improving confidence in the technique.

Photogrammetry from terrestrial cameras and manned aircraft has been used for many years to create scale diagrams and measure distances for use in traffic accident investigation and reconstruction. Due to increasing capability and availability, Unmanned Aircraft Systems (UAS), including small UAS (SUAS), are becoming a valuable, cost effective tool for collecting aerial images for photogrammetric analysis. For this study, two different SUAS were used to collect aerial imagery for photogrammetric processing using PhotoModeler software. The results show the photogrammetric measurement of an accident scene from SUAS aerial imagery provides measurements with errors well below generally accepted ranges for accident reconstruction.

In this pilot study, the authors tested whether photogrammetry can replace or supplement physical measurements made during autopsies and, based on such measurements, whether virtual computer models may be applicable in forensic reconstructions.

The author discusses the use of photogrammetry in aircraft accident scene documentation. Major Adam Cybanski is the officer responsible
for helicopter investigation at the Canadian Forces Directorate of Flight Safety in Ottawa, Canada. He is a tactical helicopter pilot with over 20 years and 2500 hours on fixed and rotary wing aircraft.

Video from Q13 Fox News in Washington State regarding the use of PhotoModeler by the Washington State Patrol. Unfortunately the video on the Q13 site is no longer available.

Over the past four years, Liscio, based in Toronto, has worked on nearly 60 cases around the world. Police use his reconstructions to test their theories of a crime. “You can start running different scenarios — what would happen if this person was a little to the left: would the trajectory still work? Or could the witness have actually seen the suspect at that point?” Liscio uses off-the-shelf 3D scanning equipment, such as the PhotoModeler Scanner made by EOS, to map entire crime scenes.