Summary: Projector Placement Planning for High Quality Visualizations
on Real-World Colored Objects
Alvin J. Law, Daniel G. Aliaga, Member, IEEE, and Aditi Majumder, Member, IEEE
Abstract--Many visualization applications benefit from displaying content on real-world objects rather than on a traditional display
(e.g., a monitor). This type of visualization display is achieved by projecting precisely controlled illumination from multiple projectors
onto the real-world colored objects. For such a task, the placement of the projectors is critical in assuring that the desired
visualization is possible. Using ad hoc projector placement may cause some appearances to suffer from color shifting due to
insufficient projector light radiance being exposed onto the physical surface. This leads to an incorrect appearance and ultimately to
a false and potentially misleading visualization.
In this paper, we present a framework to discover the optimal position and orientation of the projectors for such projection-based
visualization displays. An optimal projector placement should be able to achieve the desired visualization with minimal projector
light radiance. When determining optimal projector placement, object visibility, surface reflectance properties, and projector-surface
distance and orientation need to be considered. We first formalize a theory for appearance editing image formation and construct a
constrained linear system of equations that express when a desired novel appearance or visualization is possible given a geometric
and surface reflectance model of the physical surface. Then, we show how to apply this constrained system in an adaptive search
to efficiently discover the optimal projector placement which achieves the desired appearance. Constraints can be imposed on the
maximum radiance allowed by the projectors and the projectors' placement to support specific goals of various visualization
applications. We perform several real-world and simulated appearance edits and visualizations to demonstrate the improvement
obtained by our discovered projector placement over ad hoc projector placement.
Index Terms -- large and high-resolution displays, interaction design, mobile and ubiquitous visualization.