Niels Wouters

Design and realisation of a novel robotic manipulator for retinal surgery

Retinal Vein Occlusion (RVO) is a common retinal vascular disorder which may cause severe loss of vision. Retinal cannulation appears to be the most effective treatment, but given the small diameter of a retinal vein, it is too difficult and risky for a surgeon to perform this procedure manually. This work reports on the development of an innovative robotic manipulator to assist vitreoretinal surgeons during this procedure using a co-manipulation control strategy. The robotic manipulator features a new Remote-Center-of-Motion mechanism with four degrees of freedom. This mechanism is particularly interesting for applications in minimally invasive surgery where an instrument needs to be manoeuvred in a highly confined space around a fixed incision point. The developed manipulator is shown to be a great asset in improving the quality of retinal cannulations compared to the manual procedure. This is shown by cannulation experiments performed on a custom made eye model and an injectable retina model that effectively simulate real retinal cannulations.

Uncovering the Honeypot Effect: How Audiences Engage with Public Interactive Systems

In HCI, the honeypot effect describes how people interacting with a system passively stimulate passers-by to observe, approach and engage in an interaction. Previous research has revealed the successive engagement phases and zones of the honeypot effect. However, there is little insight into: 1) how people are stimulated to transition between phases; 2) what aspects drive the honeypot effect apart from watching others; and 3) what constraints affect its self-reinforcing performance. In this paper, we discuss the honeypot effect as a spatiotemporal model of trajectories and influences. We introduce the Honeypot Model based on the analysis of observations and interaction logs from Encounters, a public installation that interactively translated bodily movements into a dynamic visual and sonic output. In providing a model that describes trajectories and influences of audience engagement in public interactive systems, our paper seeks to inform researchers and designers to consider contextual, spatial and social factors that influence audience engagement.

StreetTalk : participative design of situated public displays for urban neighborhood interaction

As modern information communication technologies are increasingly integrated in our public environment, challenges arise to render them locally relevant and meaningful. In this paper, we describe the design and evaluation of StreetTalk, a set of situated public displays attached to house facades that were specifically designed to facilitate communication and interaction between households and their local neighborhood. We report on a participatory design process that resulted in a range of neighborhood communication concepts that reached beyond the traditional screen-based notion of public displays. Accordingly, three unique displays were deployed and critically evaluated during an eight-week in-the-wild field study, which aimed to describe the potential usefulness of making public displays more situated, such as by taking into account the individual preferences of households in terms of design and functionality, by exploring alternative means of public communication, and by facilitating content creation by lay households.

Should Public Displays be Interactive? Evaluating the Impact of Interactivity on Audience Engagement

This paper describes a comparative case study that aims to uncover the quantifiable differences between non-interactive and interactive public displays in the urban environment. The study involved a large temporary interactive public display on a central city square showing a selection of custom-made content. We have evaluated the effect on passers-by and spectators in two conditions: 1) non-interactive (2102 passers-by, 228 viewers), by showing a content loop, and 2) interactive (1676 passers-by, 257 viewers), by adding physical pushbuttons for content selection and gaming. We discuss the influence of non-interactive and interactive public displays on: 1) attracting attention, 2) engaging people, 3) improving social dynamics within and among groups of viewers, and 4) catering for the suitable time of day. Based on our observations, we provide quantitative support for the hypothesis that interactive displays are more successful than non-interactive displays to engage viewers, and to make city centers more lively and attractive.

Controlling In-the-Wild Evaluation Studies of Public Displays

In this paper, we investigate the potential of controlled in-the-wild studies as an evaluation methodology that merges the benefits of lab-based and in-the-wild studies. Our exploratory investigation builds upon a comparative, between subject experiment benchmarking different interaction features of a custom public installation that visualized a series of urban datasets. In order to evaluate the usefulness of the in-the-wild versus the controlled in-the-wild methodologies, we compared the resulting findings in terms of participant engagement, insight generation, and social interaction. We propose that a controlled in-the-wild study offers a viable alternative when evaluating more complex interaction methods in public space, hereby potentially reducing the practical efforts of in-the-wild studies to involve participants.

Synchronized wayfinding on multiple consecutively situated public displays

Our built environment is becoming increasingly equipped with public displays, many of which are networked and share the same physical location. In spite of their ubiquitous presence and inherent dynamic functionalities, the presence of multiple public displays is often not exploited, such as to solve dynamic wayfinding challenges in crowded or complex spaces. Hence, we have studied how signage can be animated onto multiple consecutively located public displays in combination with other content. This paper reports on an in-the-wild evaluation study in a real-world, metropolitan train station in order to identify the most promising design strategies to: 1) provide the notion of spatial directionality by way of animation; 2) support concurrent viewing of wayfinding with other content types, and 3) convey a sense of urgency. Our results indicate that spatially distributed animated patterns may be used to convey directions under specific spatial conditions and content combination strategies, yet their impact is limited and highly dependent on the visibility of the animated patterns on individual screens and across multiple displays.

Hyperspectral image deblurring with PCA and total variation

In this paper, we propose a novel algorithm for hyper-spectral (HS) image deblurring with principal component analysis (PCA) and total variation (TV). We first decorrelate the HS images and separate the information content from the noise by means of PCA. Then, we employ the TV method to jointly denoise and deblur the first principal components (PCs). Subsequently, noise in the last principal components is suppressed using a simple soft-thresholding scheme, for computational efficiency. Experimental results on simulated and real HS images are very encouraging.

LocaLudo: card-based workshop for interactive architecture

In this paper, we describe the design and outcomes of LocaLudo, a playful and card-based workshop that aims to involve families in the design of interactive architecture. Family members, both children and adults, were invited to build upon local experiences for informing the design of concepts that allow interaction between the house, its residents, and the neighborhood. While the creation of such concepts proved challenging, we found that an open and playful approach, and suggesting the possible use of technologies aided participants in this process. Several recurring themes were identified in the generated concepts: stimulating social contact, spreading information, reacting to negative events, and solving practical problems.

Revealing the architectural quality of media architecture

Media architecture is becoming an increasingly affordable and ubiquitous element in our built environment. As a result, architecture gains dynamic and interactive opportunities to engage with its surroundings. However, the influence of media architecture on the experience of the built environment raises the need to avoid an architectural disconnect. In this paper, we describe which design qualities support the architectural relevance of media architecture. We report on a Q Methodology survey among 22 architects that aimed to reveal the perceived architectural quality of 24 existing media architecture projects. Our analysis of the specific terminology illustrates how perceived architectural quality of media architecture relates to its ability to 1) coexist with physical characteristics of architecture; 2) augment space; 3) respond to contextual changes; and 4) communicate content that is relevant for the architectural situation.

Everybody Dance Now: Tensions between Participation and Performance in Interactive Public Installations

In this paper, we report on Encounters, an interactive public installation that provides a basis for studying the effect of dance performances on the emergence of creative, social experiences. Based on observations and interviews with dancers and participants, we identified a range of tensions that arise from integrating a staged performance with participatory interaction. These tensions occurred among both participants and performers, and influenced the social and performative experience. Based on our analysis, we propose several strategies to smoothen the integration of performative and participatory interaction. These strategies reconsider the role of the interactive installation, the effect of digital cues that draw on existing conventions, and mechanisms to direct gaze. We believe our findings and strategies are valuable to HCI researchers and performative artists seeking to design for public participation in interactive experiences.