Haptics in forensics: The possibilities and advantages in using the haptic device for reconstruction approaches in forensic science Ursula Buck a,b, *, Silvio Naether a , Marcel Braun c , Michael Thali a a University of Bern, Institute of Forensic Medicine, Buehlstrasse 20, 3012 Bern, Switzerland b Canton Police Bern, Accident Service, Schermenweg 9, 3001 Bern, Switzerland c City Police Zurich, Accident Service, Bahnhofquai 3, 8021 Zurich, Switzerland 1. Introduction The haptic technology interfaces the user via the sense of touch by applying forces and vibrations to the user. Computer haptics are algorithms, hardware and software, associated with generating and rendering the touch and feel of virtual objects. A haptic device is a true 3D interface, and gives force feedback when the cursor comes into contact with the virtual object. In this manner it is possible to sense the surface of digitized objects. Haptic devices are employed for applications in medicine, entertainment, education, industry, design and graphic arts [1]. In the medical field they are used, for example, as a medical simulator, for Computed Tomography (CT)-directed percutaneous interven- tions [2] and in image-guided surgery [3]. Furthermore, haptic devices are used for computerized forensic facial reconstruction [4]. In the forensic field, 3D technologies are gaining in importance [5–10]. Apart from forensic medical examinations (external examina- tion and autopsy), radiological cross-section technologies are used for the documentation and analysis of internal findings. 3D digitizing methods are employed for the 3D documentation of external body findings and of injury-inflicting instruments. All- in-one real-data-based 3D models of the deceased, true to scale and colour, are generated in modern computer software from the prepared digital data. This digital data is used for geometric comparison of patterned injuries with the presumed injury-inflicting instrument or for traffic accident and crime scene reconstruction. Forensic Science International 180 (2008) 86–92 ARTICLE INFO Article history: Received 20 November 2007 Received in revised form 3 June 2008 Accepted 14 July 2008 Keywords: Forensic science Haptic device Radiological scanning 3D optical scanning 3D reconstruction Virtopsy ABSTRACT Non-invasive documentation methods such as surface scanning and radiological imaging are gaining in importance in the forensic field. These three-dimensional technologies provide digital 3D data, which are processed and handled in the computer. However, the sense of touch gets lost using the virtual approach. The haptic device enables the use of the sense of touch to handle and feel digital 3D data. The multifunctional application of a haptic device for forensic approaches is evaluated and illustrated in three different cases: the representation of bone fractures of the lower extremities, by traffic accidents, in a non-invasive manner; the comparison of bone injuries with the presumed injury-inflicting instrument; and in a gunshot case, the identification of the gun by the muzzle imprint, and the reconstruction of the holding position of the gun. The 3D models of the bones are generated from the Computed Tomography (CT) images. The 3D models of the exterior injuries, the injury-inflicting tools and the bone injuries, where a higher resolution is necessary, are created by the optical surface scan. The haptic device is used in combination with the software FreeForm Modelling Plus TM for touching the surface of the 3D models to feel the minute injuries and the surface of tools, to reposition displaced bone parts and to compare an injury-causing instrument with an injury. The repositioning of 3D models in a reconstruction is easier, faster and more precisely executed by means of using the sense of touch and with the user-friendly movement in the 3D space. For representation purposes, the fracture lines of bones are coloured. This work demonstrates that the haptic device is a suitable and efficient application in forensic science. The haptic device offers a new way in the handling of digital data in the virtual 3D space. ß 2008 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: University of Bern, Institute of Forensic Medicine, IRM-Buehlstrasse 20, CH-3012 Bern, Switzerland. Tel.: +41 31 631 84 12; fax: +41 31 631 38 33. E-mail address: ursula.buck@irm.unibe.ch (U. Buck). Contents lists available at ScienceDirect Forensic Science International journal homepage: www.elsevier.com/locate/forsciint 0379-0738/$ – see front matter ß 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.forsciint.2008.07.007