We present a method for estimating the 3D shape of an object from a sequence of images captured by a hand-held device. The method is well suited to augmented reality applications in that minimal user interaction is required, and the models generated are of an appropriate form. The method proceeds by segmenting the object in every image as it is captured and using the calculated silhouette to update the current shape estimate. In contrast to previous silhouette-based modelling approaches, however, the segmentation process is informed by a 3D prior based on the previous shape estimate. A voting scheme is also introduced in order to compensate for the inevitable noise in the camera position estimates. The combination of the voting scheme with the closed-loop segmentation process provides a robust and flexible shape estimation method. We demonstrate the approach on a number of scenes where segmentation without a 3D prior would be challenging.

We present an interactive image-based modelling method for generating 3D models within an augmented reality system. Applying real time camera tracking, and high-level automated image analysis, enables more powerful modelling interactions than have previously been possible. The result is an immersive modelling process which generates accurate three dimensional models of real objects efficiently and effectively. In demonstrating the modelling process on a range of indoor and outdoor scenes, we show the flexibility it offers in enabling augmented reality applications in previously unseen environments.

Automatic placement of surveillance cameras in arbitrary buildings is a challenging task, and also one that is essential for efficient deployment of large scale surveillance networks. Existing approaches for automatic camera placement are either limited to a small number of cameras, or constrained in terms of the building layouts to which they can be applied. This paper describes a new method for determining the best placement for large numbers of cameras within arbitrary building layouts. The method takes as input a 3D model of the building, and uses a genetic algorithm to find a placement that optimises coverage and (if desired) overlap between cameras. Results are reported for an implementation of the method, including its application to a wide variety of complex buildings, both real and synthetic.

VideoTrace is a system for interactively generating realistic 3D models of objects from video---models that might be inserted into a video game, a simulation environment, or another video sequence. The user interacts with VideoTrace by tracing the shape of the object to be modelled over one or more frames of the video. By interpreting the sketch drawn by the user in light of 3D information obtained from computer vision techniques, a small number of simple 2D interactions can be used to generate a realistic 3D model. Each of the sketching operations in VideoTrace provides an intuitive and powerful means of modelling shape from video, and executes quickly enough to be used interactively. Immediate feedback allows the user to model rapidly those parts of the scene which are of interest and to the level of detail required. The combination of automated and manual reconstruction allows VideoTrace to model parts of the scene not visible, and to succeed in cases where purely automated approaches would fail.

This paper describes a method for generating a model-based reconstruction of a scene from image data. The method uses the camera models and point cloud typically generated by a structure-and-motion process as a starting point for developing a higher level model of the scene. The method relies on the user to provide a minimal amount of structural seeding information from which more complex geometry is extrapolated. The regularity typically present in man-made environments is used to minimise the interaction required, but also to improve the accuracy of fit. We demonstrate model based reconstructions obtained using this method. 1