The application of visual saliency models in objective image quality assessment: a statistical evaluation

Advances in image quality assessment have shown the potential added value of including visual attention aspects in its objective assessment. Numerous models of visual saliency are implemented and integrated in different image quality metrics (IQMs), but the gain in reliability of the resulting IQMs varies to a large extent. The causes and the trends of this variation would be highly beneficial for further improvement of IQMs, but are not fully understood. In this paper, an exhaustive statistical evaluation is conducted to justify the added value of computational saliency in objective image quality assessment, using 20 state-of-the-art saliency models and 12 best-known IQMs. Quantitative results show that the difference in predicting human fixations between saliency models is sufficient to yield a significant difference in performance gain when adding these saliency models to IQMs. However, surprisingly, the extent to which an IQM can profit from adding a saliency model does not appear to have direct relevance to how well this saliency model can predict human fixations. Our statistical analysis provides useful guidance for applying saliency models in IQMs, in terms of the effect of saliency model dependence, IQM dependence, and image distortion dependence. The testbed and software are made publicly available to the research community

User-interfaces layout optimization using eye-tracking, mouse movements and genetic algorithms

[EN] Establishing the best layout configuration for software-generated interfaces and control panels is a complex problem when they include many controls and indicators. Several methods have been developed for arranging the interface elements; however, the results are usually conceptual designs that must be manually adjusted to obtain layouts valid for real situations. Based on these considerations, in this work we propose a new automatized procedure to obtain optimal layouts for software-based interfaces. Eye-tracking and mouse-tracking data collected during the use of the interface is used to obtain the best configuration for its elements. The solutions are generated using a slicing-trees based genetic algorithm. This algorithm is able to obtain really applicable configurations that respect the geometrical restrictions of elements in the interface. Results show that this procedure increases effectiveness, efficiency and satisfaction of the users when they interact with the obtained interfaces.This work was supported by the Programa estatal de investigacion, desarrollo e innovacion orientada a los retos de la sociedad of the Government of Spain under Grant DPI 2016-79042-R.Diego-Mas, JA.; Garzon Leal, D.; Poveda Bautista, R.; Alcaide Marzal, J. (2019). User-interfaces layout optimization using eye-tracking, mouse movements and genetic algorithms. Applied Ergonomics. 78:197-209. https://doi.org/10.1016/j.apergo.2019.03.004S1972097

Investigating the mechanisms underlying fixation durations during the first year of life: a computational account

Infants’ eye-movements provide a window onto the development of cognitive functions over the first years of life. Despite considerable advances in the past decade, studying the mechanisms underlying infant fixation duration and saccadic control remains a challenge due to practical and technical constraints in infant testing. This thesis addresses these issues and investigates infant oculomotor control by presenting novel software and methods for dealing with low-quality infant data (GraFIX), a series of behavioural studies involving novel gaze-contingent and sceneviewing paradigms, and computational modelling of fixation timing throughout development. In a cross-sectional study and two longitudinal studies, participants were eye-tracked while viewing dynamic and static complex scenes, and performed gap-overlap and double-step paradigms. Fixation data from these studies were modelled in a number of simulation studies with the CRISP model of fixation durations in adults in scene viewing. Empirical results showed how fixation durations decreased with age for all viewing conditions but at different rates. Individual differences between long- and short-lookers were found across visits and viewing conditions, with static images being the most stable viewing condition. Modelling results confirmed the CRISP theoretical framework’s applicability to infant data and highlighted the influence of both cognitive processing and the developmental state of the visuo-motor system on fixation durations during the first few months of life. More specifically, while the present work suggests that infant fixation durations reflect on-line perceptual and cognitive activity similarly to adults, the individual developmental state of the visuo-motor system still affects this relationship until 10 months of age. Furthermore, results suggested that infants are already able to program saccades in two stages at 3.5 months: (1) an initial labile stage subject to cancellation and (2) a subsequent non-labile stage that cannot be cancelled. The length of the non-labile stage decreased relative to the labile stage especially from 3.5 to 5 months, indicating a greater ability to cancel saccade programs as infants grew older. In summary, the present work provides unprecedented insights into the development of fixation durations and saccadic control during the first year of life and demonstrates the benefits of mixing behavioural and computational approaches to investigate methodologically challenging research topics such as oculomotor control in infancy

Improved Saliency Mechanism for Computer Vision

The objective of this project is to find an efficient biologically plausible model for the bottom-up saliency mechanism of the human vision system (HVS) and employ it in computer vision applications. In practice, analyzing or storing all information entering the human eye at every moment is beyond the capabilities of the human neural system. The saliency mechanism controls the process of selecting and allocating attention to the most "prominent" locations in the scene, which are mostly referred to as "salient points" or "interesting points" in the literature. The same problem of information overload exists in most of the computer vision applications and an efficient visual saliency model can help reducing time consumption of the algorithm. These applications comprise, but are not limited to, automatic target detection, robotics and image and video compression.In the report herein, the general architecture of models of the HVS saliency mechanism is presented and some of the well-known models are illustrated. There are several metrics to compare saliency models; however, results from different metrics vary widely in evaluating models. Since it is important to know which models perform the best in mimicking the saliency mechanism of the human visual system, first a procedure is proposed for evaluating metrics for comparing saliency maps using a database of human fixations on approximately 1000 images. This procedure is then employed to identify the best metric. This best metric is then used to evaluate nine published bottom-up saliency models on two databases, one containing natural images and the other synthetic ones.Furthermore, a new method for normalizing feature saliency maps in the saliency detection mechanisms is introduced. Also, the best visual saliency model in the literature is modified to overcome some deficiencies by automatically selecting different parameters for different regions of the image. As an application of the models of the saliency mechanisms, a saliency mechanism with the new normalization method is then applied to dishware inspection that shows interesting results.Mechanical Engineerin

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 336)

This bibliography lists 111 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during April 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Experimental user interface design toolkit for interaction research (IDTR).

The research reported and discussed in this thesis represents a novel approach to User Interface evaluation and optimisation through cognitive modelling. This is achieved through the development and testing of a toolkit or platform titled Toolkit for Optimisation of Interface System Evolution (TOISE). The research is conducted in two main phases. In phase 1, the Adaptive Control of Thought Rational (ACT-R) cognitive architecture is used to design Simulated Users (SU) models. This allows models of user interaction to be tested on a specific User Interface (UI). In phase 2, an evolutionary algorithm is added and used to evolve and test an optimised solution to User Interface layout based on the original interface design. The thesis presents a technical background, followed by an overview of some applications in their respective fields. The core concepts behind TOISE are introduced through a discussion of the Adaptive Control of Thought “ Rational (ACT-R) architecture with a focus on the ACT-R models that are used to simulate users. The notion of adding a Genetic Algorithm optimiser is introduced and discussed in terms of the feasibility of using simulated users as the basis for automated evaluation to optimise usability. The design and implementation of TOISE is presented and discussed followed by a series of experiments that evaluate the TOISE system. While the research had to address and solve a large number of technical problems the resulting system does demonstrate potential as a platform for automated evaluation and optimisation of user interface layouts. The limitations of the system and the approach are discussed and further work is presented. It is concluded that the research is novel and shows considerable promise in terms of feasibility and potential for optimising layout for enhanced usability

Mobility and Aging: Older Drivers’ Visual Searching, Lane Keeping and Coordination

This thesis examined older drivers’ mobility and behaviour through comprehensive measurements of driver-vehicle-environment interaction and investigated the associations between driving behaviour and cognitive functions. Data were collected and analysed for 50 older drivers using eye tracking, GNSS tracking, and GIS. Results showed that poor selective attention, spatial ability and executive function in older drivers adversely affect lane keeping, visual search and coordination. Visual-motor coordination measure is sensitive and effective for driving assessment in older drivers