Outdoor Dynamic 3-D Scene Reconstruction

Existing systems for 3D reconstruction from multiple view video use controlled indoor environments with uniform illumination and backgrounds to allow accurate segmentation of dynamic foreground objects. In this paper we present a portable system for 3D reconstruction of dynamic outdoor scenes which require relatively large capture volumes with complex backgrounds and non-uniform illumination. This is motivated by the demand for 3D reconstruction of natural outdoor scenes to support film and broadcast production. Limitations of existing multiple view 3D reconstruction techniques for use in outdoor scenes are identified. Outdoor 3D scene reconstruction is performed in three stages: (1) 3D background scene modelling using spherical stereo image capture; (2) multiple view segmentation of dynamic foreground objects by simultaneous video matting across multiple views; and (3) robust 3D foreground reconstruction and multiple view segmentation refinement in the presence of segmentation and calibration errors. Evaluation is performed on several outdoor productions with complex dynamic scenes including people and animals. Results demonstrate that the proposed approach overcomes limitations of previous indoor multiple view reconstruction approaches enabling high-quality free-viewpoint rendering and 3D reference models for production

Towards achieving convincing live interaction in a mixed reality environment for television studios

The virtual studio is a form of Mixed Reality environment for creating television programmes, where the (real) actor appears to exist within an entirely virtual set. The work presented in this thesis evaluates the routes required towards developing a virtual studio that extends from current architectures in allowing realistic interactions between the actor and the virtual set in real-time. The methodologies and framework presented in this thesis is intended to support future work in this domain. Heuristic investigation is offered as a framework to analyse and provide the requirements for developing interaction within a virtual studio. In this framework a group of experts participate in case study scenarios to generate a list of requirements that guide future development of the technology. It is also concluded that this method could be used in a cyclical manner to further refine systems postdevelopment. This leads to the development of three key areas. Firstly a feedback system is presented, which tracks actor head motion within the studio and provides dynamic visual feedback relative to their current gaze location. Secondly a real-time actor/virtual set occlusion system that uses skeletal tracking data and depth information to change the relative location of virtual set elements dynamically is developed. Finally an interaction system is presented that facilitates real-time interaction between an actor and the virtual set objects, providing both single handed and bimanual interactions. Evaluation of this system highlights some common errors in mixed reality interaction, notably those arising from inaccurate hand placement when actors perform bimanual interactions. A novel two stage framework is presented that measures the magnitude of the errors in actor hand placement, and also, the perceived fidelity of the interaction from a third person viewer. The first stage of this framework quantifies the actor motion errors while completing a series of interaction tasks under varying controls. The second stage uses examples of these errors to measure the perceptual tolerance of a third person when viewing interaction errors in the end broadcast. The results from this two stage evaluation lead to the development of three methods for mitigating the actor errors, with each evaluated against its ability to aid in the visual fidelity of the interaction. It was discovered that the adapting the size of the virtual object was effective in improving the quality of the interaction, whereas adapting the colour of any exposed background did not have any apparent effects. Finally a set of guidelines based on these findings is provided to recommend appropriate solutions that can be applied for allowing interaction within live virtual studio environments that can easily be adapted for other mixed reality systems