Acquiring a Radiance Distribution to Superimpose Virtual Objects onto a Real Scene

|This paper describes a new method for superimposing virtual objects with correct shadings onto an image of a real scene. Unlike the previously proposed methods, our method can measure a radiance distribution of a real scene automatically and use it for superimposing virtual objects appropriately onto a real scene. First, a geometric model of the scene is constructed from a pair of omni-directional images by using an omni-directional stereo algorithm. Then radiance of the scene is computed from a sequence of omnidirectional images taken with di erent shutter speeds and mapped onto the constructed geometric model. The radiance distribution mapped onto the geometric model is used for rendering virtual objects superimposed onto the scene image. As a result, even for a complex radiance distribution, our method can superimpose virtual objects with convincing shadings and shadows cast onto the real scene. We successfully tested the proposed method by using real images to show its e ectiveness. Keywords| computer graphics, computer vision, augmented reality, illumination distribution measurement, omni-directional stereo algorithm