Projectors can control colors of real objects by overlaying light projection. There are a lot of studies that employ a projector-camera system to control appearance of real objects. I call this technology as projection-based appearance control in this presentation. However, almost none of them is actually used as practical applications. One of the main reason is environmental light. The most of the studies assume dark environments, which are not favorable in many practical scenes, to guarantee enough controllability of appearance. The goal of this dissertation is to increase controllability of colors in all existing projection-based appearance control system. It is connected to broaden applicability of all projection-based appearance control studies. In particular, I focused on following two from the problems caused by environmental light: 1. conventional estimating method for original appearance does not work in a dynamic light environment, 2. presentable color range of projectors decrease in a well-lit environment.

Firstly, I established robust reflectance estimation method against dynamic environmental light. Real-time reflectance estimation method is already proposed, and it is required for present desiable appearance by projection. However, the method regards constant environmental light. In practical scene, environmental light changes frequently, the system needs re-calibration in every change of environmental light. This will be problem for actual applications. To solve this problem, I established robust reflectance estimation method. With our method, our system can present absolute colors by considering reflectance and environmental light. In addition, the system become calibration-less.

Secondly, I designed a method for expanding controllable color range of projectors perceptually. Because of objects’ colors and environmental light, controllable color range of projectors become narrower. In order to expand controllable color range of projectors without changing devices or environments, our idea is controlling projection based on human perceived colors by inducing one of the visual illusion, color constancy. With our method, our system can perceptually present colors which cannot be presented physically.

With this work, controllability of color in all of the existing projection-based appearance control technology increases and applicability of them is broadened. This work is helpful to expand practical applications of projector-camera systems, and it also indicates possibility of not physically-based but perceptually-based information presentation.