Skeye was asked by the Belgian Police of the city of Genk (PG GAOZ) to assist with measuring from captured imagery from a RPA (Remote Piloted Aircraft ) above road traffic accidents. The police wanted to know what the best methodology was to acquire imagery with an RPA and how this needed to be processed so as to provide highly accurate measurements. There were two constraints for this project. The first constraint was that the flight with the RPA were not pre-programmed as this is impractical in reality. The second constant was that no reference markers were to be applied to any of the cars as these would be disturbed.
Just outside Genk a traffic accident was simulated that involved two cars. Skeye set-up twenty control points around the accident. The aim of these control points was to check if measured distances from the imagery would be similar to the same distances measured by on the ground. The distances between these control points were measured using a high grade measuring tape in combination with RTK GPS.
A number of flights were conducted at heights varying between 30 and 50 meters. The average time for a flight was no more than 5 minutes and this included take-off and landing. The acquired imagery was processed in three different manners.
- 1. Method 1: Using standard photogrammetric software and providing the software one of the 21 reference measurements.
- 2. Method 2: Using standard photogrammetric software and providing the software the ten GPS measured control points.
- 3. Method 3: Using 3Dias photogrammetric software and providing the software one of the 21 reference measurements.
The software 3DIAS (3D Incident Analysis Software) was especially developed for Incident Analysis by the Delft based company Geodelta.
The following results were obtained:
It could be concluded that sub-cm accuracy can be obtained with photogrammetry using an RPA.
Download here a more detailed report of this project.