Art as Foundation

Augmented reality (AR) allows the surgeon to represent holographic patient-specific anatomical information and surgical instruments in the physical world. To correctly superimpose virtual and physical objects, a hand-eye (HE) calibration method for mapping the virtual and physical spaces was proposed. Mathematical relationships between the virtual camera and the physical space were derived. Finally, the accuracy and robustness of the proposed HE calibration method were qualitatively and quantitatively evaluated. The proposed calibration method allows us to determine an optimal invariant spatiotemporal mapping between the virtual camera and the physical space. Qualitatively and quantitatively reliable and accurate estimates for the physical-virtual mapping transformation were verified. Consequently, imaging data and surgical instruments holograms can be precisely represented in the physical space.

Shoulder apprehension is related to changes in functional cerebral networks induced by dislocations, peripheral neuromuscular lesions and persistent mechanical glenohumeral instability consisting of micro-motion.All the damage to the osseous and soft-tissue stabilizers of the shoulder, as well as neurologic impairment persisting even after stabilization, must be properly identified in order to offer the best possible treatment to the patient.There is growing evidence supporting the use of a global multimodal approach, involving, on the one hand, shoulder ‘reafferentation’, including proprioception, mirror therapy and even cognitive behavioural approaches, and, on the other hand, surgical stabilization techniques and traditional physical therapy in order to minimize persistent micro-motion, which may help brain healing. This combined management could improve return to sport and avoid dislocation arthropathy in the long term.Cite this article: EFORT Open Rev 2018;3:550-557. DOI: 10.1302/2058-5241.3.180007

In the context of the 3DUI Contest promoted by the IEEE VR 2018, we propose 3D interaction techniques that address three distinct tasks in a virtual environment setup: climbing a ladder, controlling a quadcopter in a first-person view flight, and building a tower by stacking a series of objects. The interaction techniques were developed so the player, our 3D-athlete, has control over the events in each task, following metaphors that facilitate the use of the interface, and having status and spatial awareness supported by clear feedback cues. Thus, the player should be able to execute the tasks with precision and agility.

We describe a calibration procedure to track consumer Head Mounted Displays (HMD) using a 3rd party tracking solution. The calibration consists of registering the center of projection of the rendering hardware to a 3rd party tracked object attached to it, and is performed by matching motion datasets from the HMD built-in and 3rd party tracking solutions. We demonstrate this calibration with an augmented reality optical see-through HMD, where the correctness of the alignment is critical to the visual match of a real object by a virtual overlay. We assessed a mean error of 3mm (SD = 1mm) for objects at a distance of 70cm in the projected overlay image.

When estimating knee kinematics from skin markers and stereophotogrammetry, multi-body optimization (MBO) has provided promising results for reducing soft tissue artefacts (STA), but can still be improved. The goal of this study was to assess the performance of MBO with subject-specific knee models at high knee flexion angles (up to 110°) against knee joint kinematics measured by magnetic resonance imaging. Eight subjects were recruited. MBO with subject-specific knee models was more effective in compensating STA compared to no kinematic and spherical constraints, in particular for joint displacements. Moreover, it seems to be more reliable over large ranges of knee flexion angle. The ranges of root mean square errors for knee rotations/displacements were 3.0°–9.2°/1.3–3.5 mm for subject-specific knee models, 6.8°–8.7°/6.0–12.4 mm without kinematic constraint and 7.1°–9.8°/4.9–12.5 mm for spherical constraints.

The heat and mass transfer through the garment to maintain the heat balance between the human body and the environment is dependent on the air gap thickness underneath the garment, which in turn is affected to a great extent by the body movement. Therefore, in this study, 3D garment simulation software was quantitatively validated by comparing the air gap thickness results obtained for stationary postures simulated by 3D simulation software and measured with 3D scanning method. The aim was to assess the capability of 3D garment simulation software to accurately determine air gap thickness distribution. Moreover, the effect of differences between air gap thickness of real and virtual garments on the thermal resistance of the garments was evaluated for individual body regions. It was found that the agreement between the two methods was within the range of 10 mm for air gap thickness. This difference resulted in small differences in thermal resistance for tight (up to 0.025m2K/W) and loose fit (up to 0.013m2K/W).