Demonstration of Laser Scanning at a Crash Scene

Location: Police Academy Rocenska ulica 56 1211 Ljubljana – Šmartno Slovenia

Demonstrators: Jon Skelton, Topcon; Verica Zalovic, Geo-Centar

Intention: To capture data at a crash scene using a FARO Focus3D laser scanner. To view the data

using FARO Scene software and review the amount and quality of data. To transfer

elements of the 3D data to a 2D plan using MapScenes Pointcloud forensic software.

Scenario: The scene was made up of two cars positioned near a road junction. Various chalk

marks were placed on the road surface to indicate tyre marks and some items were

placed around the scene to simulate debris and evidence markers.

Method: To achieve the maximum coverage of the scene and to ensure high quality data, four

separate scans of the scene were undertaken. Each scan included capturing colour

digital photographs and encompassed an area of 360 degrees around each scan

position. Each scan took 6 minutes and the entire scene was captured in around 30

minutes. Due to previous heavy snow falls some areas of interest were obscured.

Result: The data was displayed and the method for the transfer from 3D to 2D paper plan

was shown. The crash scene project was completed by Jon Skelton after the

demonstration and screen shots are included in this report. They show various

stages of the work flow and the final output. The final printout is shown at fig 9 and

fig 10 and the time needed to produce this was approximately 1 hour.

Please note that during the scanning process people entered the scene and were

recorded on the scans. This results in anomalies showing in the processed results.

During operational scanning it is recommended that the scene is kept clear of staff

and vehicles.

Thursday 13th December 2012

Figure 1

A scan of crash scene showing targets (highlighted) used for joining separate scans (Scene software)

A scan of crash scene showing three measurements with annotation (Scene software)

Figure 2

Figure 3

A top down view of scanned crash scene clearly showing chalk marks and ruler on road surface

(Scene software)

Figure 4

A 3D view of the scanned crash scene

Figure 5

A top down view showing draft linework being placed on the 3D point cloud (MapScenes software)

Figure 6

A 3D grey scale view showing draft linework placed on road surface ready for transferring to 2D CAD

window for drawing.

Figure 7

The 2D CAD window showing the linework automatically transferred from the 3D point cloud.

Symbols and text have been added for explanation and clarity.

Figure 8

The 2D CAD window showing a zoomed in area of the scene. This is now ready for printing.

Figure 9

An example of a 2D print of the crash scene with a print border. Two separate viewports are shown

with different scales. Dimensions have been switched off in this example.

.

An example of a 2D print of the crash scene with a print border. Two separate viewports are shown

with different scales. Dimensions have been switched on in this example

Figure 10