Three dimensional measurements (such as photogrammetry, Time of Flight, Structure from Motion or Structured Light techniques) are becoming a standard in the crime scene documentation process. The usage of 3D measurement techniques provide an opportunity to prepare more insightful investigation and helps to show every trace in the context of the entire crime scene. In this paper we would like to present a hierarchical, three-dimensional measurement system that is designed for crime scenes documentation process. Our system reflects the actual standards in crime scene documentation process – it is designed to perform measurement in two stages. First stage of documentation, the most general, is prepared with a scanner with relatively low spatial resolution but also big measuring volume – it is used for the whole scene documentation. Second stage is much more detailed: high resolution but smaller size of measuring volume for areas that required more detailed approach. The documentation process is supervised by a specialised application CrimeView3D, that is a software platform for measurements management (connecting with scanners and carrying out measurements, automatic or semi-automatic data registration in the real time) and data visualisation (3D visualisation of documented scenes). It also provides a series of useful tools for forensic technicians: virtual measuring tape, searching for sources of blood spatter, virtual walk on the crime scene and many others. In this paper we present our measuring system and the developed software. We also provide an outcome from research on metrological validation of scanners that was performed according to VDI/VDE standard. We present a CrimeView3D – a software-platform that was developed to manage the crime scene documentation process. We also present an outcome from measurement sessions that were conducted on real crime scenes with cooperation with Technicians from Central Forensic Laboratory of Police.
In this paper we focus on integrating multi-resolution data from different range sensors into complete 3D model. To simplify the process of building high-resolution model, we propose to create hierarchical structure of data, which contains measurements collected with both time of flight scanner and structured light projection system. Two approaches of view integration are compared with each other to formulate conclusion if combining data from different range sensors allows to improve integration process or leads to data redundancy. According to the first approach, data at higher resolution are mapped on those at lower resolution according to interest features extracted in the datasets. Interest points are calculated with Harris detector on base of curvature and texture (when available) and described with designed descriptors. Second approach assumes that only data at the highest resolution can be used and no reference is involved in integration process. At the end, the summarizing remarks are formulated according to the test results conducted on real 3D measurements.