A projector-camera system with real-time photometric adaptation for dynamic environments

Projection systems can be used to implement augmented reality, as well as to create both displays and interfaces on ordinary surfaces. Ordinary surfaces have varying reflectance, color, and geometry. Current methods use a camera to account for these variations, but are fundamentally limited since they assume the camera, projector, and scene are static. In this article, we describe a technique for photometrically adaptive projection that makes it possible to handle a dynamic environment. We begin by presenting a co-axial projector-camera system. It consists of a camera and beam splitter, which attaches to an off-the-shelf projector. The co-axial design makes geometric calibration scene-independent. To handle photometric changes, our method uses the errors between the desired and measured appearance of the projected image. A key novel aspect of our algorithm is that we combine a physics-based model with dynamic feedback to achieve real time adaptation to the changing environment. We verify our algorithm through a wide variety of experiments. We show that it is accurate and runs in real-time. Our algorithm moves beyond the limits of a static environment to make real-time color compensation in a dynamic environment possible. It can be applied broadly to assist HCI, visualization, shape recovery, and entertainment applications.