Comparison of photogrammetry and structured light scanning for imaging remains at various stages of decomposition using domestic pigs: A pilot project

The use of advanced scanning technologies (ASTs) is advantageous for many aspects of the criminal investigation process, including documenting, assessing, and preserving evidence. This pilot project focuses on the application of reflective imaging modalities, specifically photogrammetry and structured light scanning (SLS), to pig mandibles (as proxies for humans), at various stages of decomposition. This research aims to determine if these technologies can be utilised in documenting remains at differing stages of decomposition in an outdoor crime scene scenario. This is achieved by assessing the accuracy of the resulting models created using the technologies at all stages of decomposition, and the feasibility of using these technologies in a simulated outdoor crime scene environment. The results highlight that both photogrammetry and SLS can create accurate models of remains in advanced decomposition and skeletonisation; however, issues were encountered when imaging remains in the early stages of decomposition. Photogrammetry was able to accurately recreate the colour and texture information of the fresh remains, where SLS could not. The project found that both photogrammetry and SLS are easy to use in the field; however, the SLS model used required additional equipment that created logistical complications. The results can assist in indicating which AST to employ to image remains in various stages of decomposition.