Shadowless Projection Mapping for Tabletop Workspaces with Synthetic Aperture Projector

TL;DR

This paper presents a novel shadowless projection mapping system using densely arranged projectors for tabletop AR, eliminating shadows without computational delay and enhancing material perception.

Contribution

Introduces a synthetic-aperture projection mapping system with offline blur compensation, enabling delay-free, shadowless AR projection for tabletop environments.

Findings

Achieves delay-free, shadowless projection without computational compensation.

Develops an offline blur compensation method independent of projector count.

Defines and minimizes the sense of projection (SoP) for improved material perception.

Abstract

Projection mapping (PM) enables augmented reality (AR) experiences without requiring users to wear head-mounted displays and supports multi-user interaction. It is regarded as a promising technology for a variety of applications in which users interact with content superimposed onto augmented objects in tabletop workspaces, including remote collaboration, healthcare, industrial design, urban planning, artwork creation, and office work. However, conventional PM systems often suffer from projection shadows when users occlude the light path. Prior approaches employing multiple distributed projectors can compensate for occlusion, but suffer from latency due to computational processing, degrading the user experience. In this research, we introduce a synthetic-aperture PM system that uses a significantly larger number of projectors, arranged densely in the environment, to achieve delay-free, shadowless projection for tabletop workspaces without requiring computational compensation. To address spatial resolution degradation caused by subpixel misalignment among overlaid projections, we develop and validate an offline blur compensation method whose computation time remains independent of the number of projectors. Furthermore, we demonstrate that our shadowless PM plays a critical role in achieving a fundamental goal of PM: altering material properties without evoking projection-like impression. Specifically, we define this perceptual impression as ``sense of projection (SoP)'' and establish a PM design framework to minimize the SoP based on user studies.