Use of 3D Digital Photography in Equine Medicine and Surgery

Photogrammetry is the science of determining the geometry of an object based on photographic images. When this is performed on the basis of stereoscopic or pairs of images then it is referred to as stereo-photogrammetry. Next to laser scanning methods, photogrammetric techniques are strongly rooted in crime scene investigations or accident reconstructions but they have also readily been adopted for other purposes (architecture, design, medical imaging etc.). Use of digital, photographic data for spatial reconstruction and 3-dimensional (3D) modelling encompasses the creation of point clouds representative of the object to be modelled which are subsequently converted into a triangulated network or mesh and surfaced to result in a virtual, ‘life-like’ simulation. On the basis of these 3D computer simulations simple distance or angle measurements but also more elaborate volume or surface area measurements of objects or regions of interest can be performed. Next to the benefit of assessing novel parameters, stereo-photogrammetric techniques are also expected to be less affected by measurement error due to variations in photographic perspective. Reports of 2D photographic assessments of equine conformation and wound healing underline the potential utility of this 3D approach (Anderson and McIlwraith 2004; Dart et al.2009; Dyson et al. 2011). Here we report on our experiences using a commercial software program (Photomodeler Scanner, EOS Systems) in combination with a standard digital camera, and a commercially available 3D wound imaging system (Eykona Medical). The self-developed software and camera system was tested in the context of 3D wound and foot imaging but other applications including the assessment of limb conformation and intraoperative endoscopic imaging were also explored. [...]