ABSTRACT
One of the biggest challenges in the investigation of fire and explosion scenes is to properly document all important features as the examination continues because the physical remains will often have to be dismantled and moved to provide access to all the relevant physical evidence (often under a great deal of debris). Such documentation has traditionally been carried out using a camera and a tape measure which is time consuming and potentially dangerous. In the late 1990s, instrument companies introduced 3D laser scanning to largely automate the tedious process of point-by-point measurements with a tape measure or a laser-based Total Station. Today’s 3D laser scanners can take tens of thousands, even millions, of measurements per second creating a “point cloud” of data that can be manipulated to recreate in virtual reality all the dimensional relationships of even the largest scenes. When coupled with digital images these instruments can capture, a true-color 3D image can be created to preserve the appearance of the scene with dimensional accuracy within a few millimeters at 100m. A single scan takes only a few minutes and multiple scans can be linked together to recreate 3D models of even the most complex scenes. While the technology is not inexpensive, many public agencies across the United States have implemented 3D laser scanning for the documentation of fire and explosion scenes, vehicle accidents, crime scenes, and structural collapses.
Scene documentation and event reconstructions based on the data extrapolated using the 3D laser technology have already been accepted by U.S. courts as accurate and reliable scientific evidence on which to base criminal and civil cases. Laser scanning allows rapid capture of critical data with higher accuracy than the traditional methods.
The ethical issues may be misrepresenting and misusing assurances of accuracy when the data collected are used in reconstructions. What guarantees can the user offer the court as to the reliability of the interpretation if the accuracy of the data used is suspect? STET
