A case study of 3DF Zephyr in evidence-led vehicle crash forensics

 
Photogrammetry, Forensics, Documentation

 
All the following case study data are courtesy of Compass Kinetics Inc., which uses 3DF Zephyr to create scans that are then used for forensics analysis as their business focuses on motorcycle safety, accident reconstruction, consulting and expert witness services. The following models have been edited to remove personal information.
 

Sideswiped bus, laser scanner + photogrammetry textured mesh

This data shows minimal damage of a sideswiped bus by a motorcycle. While the damage is minimum, it is well captured and it shows a great example of laser scan and photogrammetry working together, with the photogrammetry data (667 photos) being used to recolorize the geometry (49 scans).

Fig. 1a. General view – geometry (left) and texture (right). © Compass Kinetics Inc.

Fig. 1b. 3D model in measurement context. © Compass Kinetics Inc.

Click the above thumbnail to load the 3D model. © Compass Kinetics Inc.

A similar example of photogrammetry (with only 46 photos for texturing) working hand in hand with an external geometry source (in this case an Artec Leo) can be found with the 3D model below:

Click the above thumbnail to load the 3D model. © Compass Kinetics Inc.

Honda HR-V – Back impact, photogrammetry textured mesh

This data shows a Honda HR-V that was struck from behind by a Harley Davidson motorcycle then lost control and rolled-over down an embankment. Pure photogrammetry (215 photos) textured mesh reconstruction.

Fig. 2. Rear view – geometry (left) and texture (right). © Compass Kinetics Inc.

Click the above thumbnail to load the 3D model. © Compass Kinetics Inc.

Ducati Monster – Frontal Impact, structured light scanner + photogrammetry

This dataset of a Ducati Monster bike shows a frontal impact into the left fender of a Toyota Prius was acquired with an Artec Leo Mesh scanner, and recolorized in 3DF Zephyr by merging it to a photogrammetry workspace of only 75 photos.

Fig. 3. Side view – geometry (left) and texture (right). © Compass Kinetics Inc.

Click the above thumbnail to load the 3D model. © Compass Kinetics Inc.

Subaru Crosstrek – Right Side Impact, Gaussian Splat

This dataset of a 2018 Subaru Crosstek crashed veichle was originally delivered as laser scanned + photogrammetry dataset. However, this particular example showcases also the Gaussian Splatting abilities of 3DF Zephyr: from only 33 photos (one single orbit at one height) the Gaussian Splatting was produced by zephyr. You can load and explore a simplified version of the splat in the viewer below. Note how notorious difficult surfaces (such as glass) are well rendered as long as there is visibility from the cameras – of course, the further you stray from the original photos, worse is the result (especially noticeable on the roof, due to missing imagery).

Fig. 4. Side view – textured mesh (left) and gaussian splatting (right). © Compass Kinetics Inc.

Click the above thumbnail to load the Gaussian Splatting. © Compass Kinetics Inc.