Collaborative view-aligned annotations in web-based 3D medical data visualization

the paper presents our web-based 3D medical data visualization framework with emphasis on user collaboration. The framework supports visualization of volumetric data and 3D meshes in web browsers. The paper focuses on integration of user-shareable 3D view-aligned hand drawn or written annotations into the visualization framework. Annotations are created on separate transparent canvases which are aligned with selected views. View parameters are part of annotations and can be shared with other users over the network. Our implementation allows for real-time sharing of annotations during creation. Annotations from the same or different users can be overlaid within the same view. Annotations were implemented through adaptation of the framework's rendering pipeline, which allows for combining multiple visualization layers into a unified final render. View aligned annotations were added in addition to text annotations pinned to 3D locations on the displayed model. In the framework, users can list through all annotations, whereby upon selection of a 3D view-aligned annotation the camera is positioned according to the stored parameters and the annotation is displayed.