Ian Davies

Real-time spatiotemporal stereo matching using the dual-cross-bilateral grid

We introduce a real-time stereo matching technique based on a reformulation of Yoon and Kweons adaptive support weights algorithm [1]. Our implementation uses the bilateral grid to achieve a speedup of 200× compared to a straightforward full-kernel GPU implementation, making it the fastest technique on the Middlebury website. We introduce a colour component into our greyscale approach to recover precision and increase discriminability. Using our implementation, we speed up spatialdepth superresolution 100×. We further present a spatiotemporal stereo matching approach based on our technique that incorporates temporal evidence in real time (>14 fps). Our technique visibly reduces flickering and outperforms per-frame approaches in the presence of image noise. We have created five synthetic stereo videos, with ground truth disparity maps, to quantitatively evaluate depth estimation from stereo video. Source code and datasets are available on our project website.

WebSurface: an interface for co-located collaborative information gathering

Co-located collaborative Web browsing is a relatively common task and yet is poorly supported by conventional tools. Prior research in this area has focused on adapting conventional browsing interfaces to add collaboration support. We propose an alternative approach, drawing on ideas from tabletop interfaces. We present WebSurface, a novel tabletop interface for collaborative Web browsing. WebSurface explores two design challenges of this approach: providing sufficient resolution for legible text; and navigating through information. We report our early experiences with an exploratory user study, in which pairs of collaborators gathered information using WebSurface. The findings suggest that a tabletop approach for collaborative Web browsing can help address limitations of conventional tools, and presents beneficial affordances for information layout.

Predicting stereoscopic viewing comfort using a coherence-based computational model

We introduce a novel computational model for objectively assessing the visual comfort of stereoscopic 3D imagery. Our model integrates research in visual perception with tools from stereo computer vision to quantify the degree of stereo coherence between both stereo half-images. We show that the coherence scores computed by our model strongly correlate with human comfort ratings using a perceptual study of 20 participants rating 80 images each. Based on our experiments, we further propose a taxonomy of stereo coherence issues which affect viewing comfort, and propose a set of computational tools that extend our model to identify and localise stereo coherence issues from stereoscopic 3D images.

Multimodal inference for driver-vehicle interaction

In this paper we present a novel system for driver-vehicle interaction which combines speech recognition with facial-expression recognition to increase intention recognition accuracy in the presence of engine- and road-noise. Our system would allow drivers to interact with in-car devices such as satellite navigation and other telematic or control systems. We describe a pilot study and experiment in which we tested the system, and show that multimodal fusion of speech and facial expression recognition provides higher accuracy than either would do alone.

Supporting Scalable Data Sharing in Online Education

Online educational tools often generate learning data, and sharing such data between tutors and students can often improve learning outcomes. Unfortunately the process of sharing learning data today is not always transparent to students. Our aim is to improve the transparency and user control aspects of sharing data whilst maintaining the educational utility of data sharing between tutors and students. To do so, we start by surveying the possible methods of sharing data, and we use this to design a token-based scheme for facilitating data sharing. We implemented our scheme and observed it in use by 7,798 students over the course of one year. We find that our proposed scheme provides a good balance between transparency, user control, educational utility and scalability.

Equality: A Tool for Free-form Equation Editing

We describe a new tool, Equality, for equation entry using free-form layout of components drawn from a palette of symbols. Our approach is designed to enable learners to easily manipulate the structure of their equations, to be functional in both desktop and mobile environments, and to minimize the amount of learning required to use the tool. We present the results of a study comparing a prototype of our approach with Microsoft Equation Editor using a desktop machine. The initial results are promising with participants reporting that the mechanism is easy to learn and an easy way to manipulate their equations. We report the results of the study and the views of the participants and identify how these will inform the future development of Equality.