Magnoramas: Magnifying dioramas for precise annotations in asymmetric 3D teleconsultation

When users create hand-drawn annotations in Virtual Reality they often reach their physical limits in terms of precision, especially if the region to be annotated is small. One intuitive solution employs magnification beyond natural scale. However, scaling the whole environment results in wrong assumptions about the coherence between physical and virtual space. In this paper, we introduce Mag-noramas, a novel interaction method for selecting and extracting a region of interest that the user can subsequently scale and transform inside the virtual space. Our technique enhances the user's capabilities to perform supernaturally precise virtual annotations on virtual objects. We explored our technique in a user study within asimplified clinical scenario of a teleconsultation-supported craniectomy procedure that requires accurate annotations on a human head. Teleconsultation was performed asymmetrically between a remote expert in Virtual Reality that collaborated with a local user through Augmented Reality. The remote expert operates inside a reconstructed environment, captured from RGB-D sensors at the local site, and is embodied by an avatar to establish co-presence. The results show that Magnoramas significantly improve the precision of annotations while preserving usability and perceived presence measures compared to the baseline method. By hiding the 3D reconstruction while keeping the Magnorama, users can intentionally choose to lower their perceived social presence and focus on their tasks.