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User-Centered Evaluation of the Virtual Binocular Interface
Abstract
This paper describes a full-body pointing interface based on the mimicking of the use of binoculars, the Virtual Binocular Interface. This interface is a component of the interactive installation "Viaggiatori di Sguardo", located at Palazzo Ducale, Genova, Italy, and visited by more than 5,000 visitors so far. This paper focuses on the evaluation of such an interface. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.
The paper demonstrates the Polish version of Device Assessment Questionnaire. Adaptation process was made in order to create the universal tool for the assessment of pointing devices other than keyboard, as it is intended in ISO9241-9 standard. The authors’ main purpose was to include in the adaptation process some of the problems of psychological rather than the content or language nature. These problems are associated with the uncertainty of those respondents, especially people with disabilities, in the subject of evaluation and excessive internal attribution (assessment of their own competencies and not the characteristics of the device).The results of three studies with an adapted diagnostic tool for comfort of work are presented. Obtained study results show compliance with the Standard, versatility and flexibility of the Questionnaire.
Optical flow cannot be computed locally, since only one independent measurement is available from the image sequence at a point, while the flow velocity has two components. A second constraint is needed. A method for finding the optical flow pattern is presented which assumes that the apparent velocity of the brightness pattern varies smoothly almost everywhere in the image. An iterative implementation is shown which successfully computes the optical flow for a number of synthetic image sequences. The algorithm is robust in that it can handle image sequences that are quantized rather coarsely in space and time. It is also insensitive to quantization of brightness levels and additive noise. Examples are included where the assumption of smoothness is violated at singular points or along lines in the image.
The IS0 9241, Part 9 Draft International Standard for testing
computer pointing devices proposes an evaluation of performance and
comfort. In this paper we evaluate the scientific validity and
practicality of these dimensions for two pointing devices for
laptop computers, a finger-controlled isometric joystick and a
touchpad. Using a between-subjects design, evaluation of
performance using the measure of throughput was done for
one-direction and multi-directional pointing and selecting. Results
show a significant difference in throughput for the
multi-directional task, with the joystick 27% higher; results for
the one-direction task were non-significant. After the experiment,
participants rated the device for comfort, including operation,
fatigue, and usability. The questionnaire showed no overall
difference in the responses, and a significant statistical
difference in only the question concerning force required to
operate the device - the joystick requiring slightly more force.
The paper concludes with a discussion of problems in implementing
the IS0 standard and recommendations for improvement.
The HCI community uses at least four different formulas for Fitts' law. Each of them is derived from Shannon's information theory. This raises the question which formula is wrong and which is right. While the HCI community on the one hand gives free choice for the formula, it demands good statistical values for the evaluation on the other hand. From a scientific point of view this situation is not satisfying.
Image registration finds a variety of applications in computer vision. Unfortunately, traditional image registration techniques tend to be costly. We present a new image registration technique that makes use of the spatial intensity gradient of the images to find a good match using a type of Newton-Raphson iteration. Our technique is taster because it examines far fewer potential matches between the images than existing techniques Furthermore, this registration technique can be generalized to handle rotation, scaling and shearing. We show how our technique can be adapted tor use in a stereo vision system.
This paper describes the main novel developments which have been introduced and experimented with in "Viaggiatori di Sguardo", a permanent interactive installation. The objectives and resulting interaction design choices are briefly explained, and the system architecture briefly sketched. Then, the paper focuses on the novel full-body pointing interaction mechanism based on the mimicking of the use of binoculars. The permanent installation "Viaggiatori di Sguardo" was opened on December 2009 at Palazzo Ducale, Fondazione per la Cultura, Genova, and has been visited up to now by about 5,000 visitors. Results from the evaluation of such a novel interface are presented, and future developments briefly discussed.
This paper makes seven recommendations to HCI researchers wishing to construct Fitts’ law models for either movement time prediction, or for the comparison of conditions in an experiment. These seven recommendations support (and in some cases supplement) the methods described in the recent ISO 9241-9 standard on the evaluation of pointing devices. In addition to improving the robustness of Fitts’ law models, these recommendations (if widely employed) will improve the comparability and consistency of forthcoming publications. Arguments to support these recommendations are presented, as are concise reviews of 24 published Fitts’ law models of the mouse, and 9 studies that used the new ISO standard.
The work reported here is a contribution to the study of a complex motor behavior, viewed globally. The question raised is the nature of the process by which an environment-sensorimotricity coupling is organized. The material is the trajectory of a constrained free climbing task, and the main concept is entropy. The entropy of the climber's trajectory is used to measure the degree of structuring in the successive states of the subject-environment system during the learning of a complex task. It will be shown that the entropy of the trajectory decreases as learning progresses, and that the shape of the entropy curve is a function of the climber's level of expertise. A model of constraint relaxation is proposed to describe the learning process. Then, based on a theory of probabilistic inference, an attemp is made to show that this natural biological process obeys the thermodynamic laws of neural networks.
In view of the difficulties in evaluating computer pointing devices across different tasks within dynamic and complex systems, new performance measures are needed. This paper proposes seven new accuracy measures to elicit (sometimes subtle) differences among devices in precision pointing tasks. The measures are target re-entry, task axis crossing, movement direction change, orthogonal direction change, movement variability, movement error, and movement offset. Unlike movement time, error rate, and throughput, which are based on a single measurement per trial, the new measures capture aspects of movement behaviour during a trial. The theoretical basis and computational techniques for the measures are described, with examples given. An evaluation with four pointing devices was conducted to validate the measures. A causal relationship to pointing device efficiency (viz. throughput) was found, as was an ability to discriminate among devices in situations where differences did not otherwise appear. Implications for pointing device research are discussed.
This paper presents some results of a research work concerning algorithms and computational models for real-time analysis of expressive gesture in full-body human movement. As a main concrete result of our research work, we present a collection of algorithms and related software modules for the EyesWeb open architecture (freely available from www.eyesweb.org). These software modules, collected in the EyesWeb Expressive Gesture Processing Library, have been used in real scenarios and applications, mainly in the fields of performing arts, therapy and rehabilitation, museum interactive installations, and other immersive augmented reality and cooperative virtual environment applications. The work has been carried out at DIST – InfoMus Lab in the framework of the EU IST Project MEGA (Multisensory Expressive Gesture Applications,
www.megaproject.org
).
Reports of 3 experiments testing the hypothesis that the average duration of responses is directly proportional to the minimum average amount of information per response. The results show that the rate of performance is approximately constant over a wide range of movement amplitude and tolerance limits. This supports the thesis that "the performance capacity of the human motor system plus its associated visual and proprioceptive feedback mechanisms, when measured in information units, is relatively constant over a considerable range of task conditions." 25 references. (PsycINFO Database Record (c) 2006 APA, all rights reserved).
Context and emotion aware visual interaction
- N Bianchi-Berthouze
- P Mussio
- N. Bianchi-Berthouze
Bianchi-Berthouze, N., Mussio, P.: Context and emotion aware visual interaction. Journal of Visual Languages and Computing 16, 383–385 (2005)