Equitable access to the digital economy is predicated on the usability of the devices that are used to access electronic goods and services, with computers being the primary mechanism for many users by which this is currently done. For novice users with special interaction requirements, current arrangements for enabling accessibility support are suboptimal. Older users in particular require special consideration with regards to the design of software support packages to ensure the burden of knowledge required to configure a system is reasonable. This article describes the ACCESS Framework, a novel open-source, plug-in enabled software framework designed to address some of the issues around providing accessibility support on the desktop. The framework employs a system through which corrections are successively adapted to an individual user's preferences. Through empirical work with older adults, the framework has been shown to provide an understandable, appropriate, and effective way to enable accessibility support.

How to motivate and support behaviour change through design is becoming of increasing interest to the CHI community. In this paper, we present our experiences of building systems that motivate people to engage in upper limb rehabilitation exercise after stroke. We report on participatory design work with four stroke survivors to develop a holistic understanding of their motivation and rehabilitation needs, and to construct and deploy engaging interactive systems that satisfy these. We reflect on the limits of motivational theories in trying to design for the lived experience of motivation and highlight lessons learnt around: helping people articulate what motivates them; balancing work, duty, fun; supporting motivation over time; and understanding the wider social context. From these we identify design guidelines that can inform a toolkit approach to support both scalability and personalisability.

Statistical shape models are often learned from examples based on landmark correspondences between annotated examples. A method is proposed for learning such models from contours with inconsistent bifurcations and loops. Automatic segmentation of tibial and femoral contours in knee X-ray images is investigated as a step towards reliable, quantitative radiographic analysis of osteoarthritis for diagnosis and assessment of progression. Results are presented using various features, the Mahalanobis distance, distance weighted K-nearest neighbours, and two relevance vector machine-based methods as quality of fit measure.

A probabilistic method is proposed for segmentation of multiple objects that overlap or are in close proximity to one another. A likelihood function is formulated that explicitly models overlapping object appearance. Priors on global appearance and geometry (including shape) are learned from example images. Markov chain Monte Carlo methods are used to obtain samples from a posterior distribution over model parameters from which expectations can be estimated. The method is described in detail for the problem of segmenting femur and tibia in x-ray images. The result is a probabilistic segmentation that quantifies uncertainty so that measurements such as joint space can be made with associated uncertainty.

www.computing.dundee.ac.uk/projects/Vision Statistical shape models are often learned from examples based on landmark correspondences between annotated examples. A method is proposed for learning such models from contours with inconsistent bifurcations and loops. It is evaluated on the task of segmenting tibial contours in knee radiographs. Results are presented using various features, distance weighted K−nearest neighbours and differing eigenspace shape constraints. 1

The need for intubated patients, within the intensive care setting, to communicate more effectively led to the development of ICU-Talk, an augmentative and alternative communication aid. The communication aid contains a database containing both core and patient-specific vocabulary. Many users of communication aids can provide direct input into the vocabulary, but intensive care patients are not in this position. This paper discusses the methods chosen to gather the vocabulary for an intensive care setting.

A Multi-disciplinary project staffed by personnel from nursing, computer science and speech and language therapy developed a computer based communication aid called ICU-Talk. This device has been designed specifically for intubated patients in hospital intensive care units. The ICU-Talk device was trialled with real patients. This paper reports the challenges faced when developing a device for this patient group and environment. A description of the methods used to produce ICU-Talk and results from the trials will be presented.

A likelihood formulation for human tracking is presented based upon matching feature statistics on the surface of an articulated 3D model. A benefit of such a formulation over current techniques is that it provides a dense, object-based cue. Multi-dimensional histograms are used to represent the feature distributions. Different histogram similarity measures are evaluated for tracking purposes. An on-line region grouping algorithm, driven by prior knowledge of clothing structure, is derived that improves the appearance estimation and computational efficiency. Finally, we demonstrate that the smooth, broad likelihood response allows efficient inference using coarse sampling and local optimisation. Results from tracking real world sequences are presented.

Virtual colonoscopy is a non-invasive technique with the potential for wide application in the early detection of colorectal cancer. Unfortunately, to be clinically useful, it is reliant on the rapid visualisation of three-dimensional (3D) data using personal computers. This is not possible using current visualisation techniques. We present a novel method to accelerate volume rendering via ray casting as used in virtual colonoscopy. The method uses a space leaping technique in which the space inside the colon is approximated by maximal spheres constructed using the distance transform of the cavity. These spheres enable subsequent ray casting to traverse the space in an efficient way. The method has been implemented on a personal computer and is approximately 2.9 times faster when compared to the usual ray casting method for virtual colonoscopy. Potential uses of this method extend beyond virtual colonoscopy to all endoscopic applications and indeed any volume rendering application involving voxels with uniform properties.

This paper details the development of ICU-Talk, a computer-based communication aid. This aid has been designed specifically for patients who are temporarily unable to communicate due to intubation and/or ventilation within a hospital intensive care unit (ICU). The very specific needs of this client group have been considered by the multi-disciplinary research team and incorporated into the design of the system.

Analysis has shown that a proportion of motor vehicle accidents are caused by driver inattention induced by the operation of secondary controls, e.g. radio and climate controls. We have developed a novel, prototype, finger-pointing interface for operating such controls. The current physical controls are replaced by a computer interface, which has the advantage of being situated much closer to the driver's normal line of sight. This interface is operated by the driver using pointing gestures that will ultimately be identified using computer vision. The potential safety benefits that may accrue from this interface are outlined. The prototype interface currently uses an electromagnetic sensor to determine the direction of the pointing gesture. This paper describes this prototype and reports preliminary results from use of the graphical user interface.

The paper describes a computer vision system for tracking a driver's hands. The applications of such a system are discussed with particular attention given to the control of a novel vehicle systems interface. This interface is controlled by pointing at the required function on a display mounted behind the top of the steering wheel. The vision system must detect and track the driver's hands to allow efficient recovery of a search space in which to look for a pointing finger. Cameras mounted above the driver provide images of the steering wheel area. The scene is segmented using adaptive background and foreground models. A distance transform is applied to the resulting contours. A geometric model is fitted to the resulting distance map by maximising an objective function over the model parameters in a local search space defined by the output of a Kalman filter. The appearance-based model fitting process can resolve ambiguous situations such as the hands touching or crossing, and parting again. The system is demonstrated running at 10 Hz on a standard PC.