3D Laser Scanning Flashcards
What is 3D laser scanning?
Also known as LiDAR
Sureveying method that measures the distance to a target by illuminating it with a puled laser light creating a 3D representation of the scanned area
What can 3D laser scanning capture?
- Capture crime scenes in 3D
- Record 1 million points per second
- Fly through virtual scene and display complex forensic evidence
How is the evidence visualised?
- Scene views
- Evidence incorporation
- Experiments and demonstrations
- Reconstructions
- Virtual ‘scene visits’
What is photogrammetry?
Specialised software that can use these images captured in a specific manner and create 3D models of the area using photogrammetry.
What is photogrammetry defined as?
Defined as the art, science and technology of obtaining reliable information about physical objects and the environment through processes of recording, measuring and interpreting photographic images
5 visual evidence advantages?
- Increases attention span and comprehension
- Improvements in ‘weight’ given to evidence
- Simplifies complex evidence
- Improved efficiency
- CSI effect: modern jury member is comfortable with 3D
4 visual evidence disadvantages?
- Seeing is believing
- Unrealistic visualisation of a scene
- Availability and affordability
- Representation of uncertainty
Technical review of data: The pros
3
- Reliability (peer review data that can be trusted)
- Repeatability (data that can be taken by another analysit and replicated)
- Admissibility (data that can be trusted by a court of law and accepted into evidence and data that is difficult to challenge on the ground of accuracy)
Technical review of data: Cons
1
- Time/resource (time is precious given other tasks, sometimes almost double the workload, handbrake to efficiency and progress, dedicated team needed)
2 other ways of collecting photographic material for photogrammetry?
- Handheld device
- Drone
Cons with drones?
- Have to follow set of rules e.g. cannot record through other peoples windows, difficult when close proximity to another house
Pros with drones?
- Very quick
- Can pick up things from areial view that maybe 3D scanner may not have
Intergrated evidence
- When a crime scene is reconstructed and a visual walkthrough of the area is available due to 3D scanning, photos of real evidence may be integrated. For example, if a house was a crime scene and luminol was used in the bathroom, the visual walkthrough could move into the bathroom and by clicking on the sink, a photo of a real life luminol test that occurred there can be shown.
- FLoor plans can also be shown
