Digital Image Processing

This book presents several recent advances that are related or fall under the umbrella of 'digital image processing', with the purpose of providing an insight into the possibilities offered by digital image processing algorithms in various fields. The presented mathematical algorithms are accompanied by graphical representations and illustrative examples for an enhanced readability. The chapters are written in a manner that allows even a reader with basic experience and knowledge in the digital image processing field to properly understand the presented algorithms. Concurrently, the structure of the information in this book is such that fellow scientists will be able to use it to push the development of the presented subjects even further

An investigation to determine the influence of illumination sources on colour discrimination in normal subjects and smokers

Accurate colour vision testing requires using the correct illumination. With the plethora of 'daylight' lamps available, is there a cost-effective alternative to the discontinued MacBeth Easel lamp? Smoking is a known risk factor for macula degeneration. As the macula is responsible for colour discrimination, any toxin that affects it has the potential to influence colour discrimination. Aims: To find a costeffective light source for colour vision testing. To investigate the effect of smoking on colour discrimination. To explore how deuteranomalous trichromats compare with normal trichromats. Methods: Using the Ishihara colour vision test subjects were classified into the groups: 'Normal/Control', 'Smoker/Test', and 'Case Study' (subjects who failed the screening test and did not smoke). They completed the Farnsworth Munsell 100 Hue test under each of the three light sources: Phillips EcoHalo Twist (tungsten halogen - THL), Kosnic KCF07ALU/GU10-865 (compact fluorescent- CFL), and Deal Guardian Ltd. GU103X2WA4B-60 (light-emitting diode - LED) Results: 42 subjects took part in the study: 18 in the Normal/Control group, 18 in the Smoker/Test group, and 6 in the Case Study group. For the Normal/Control group the total error scores (TESs) were significantly lower with the CFL than with the THL (p = 0.017) as it was for the Case Study group (p = 0.009). No significant differences were found between the Normal/Control group and the Smoker/Test group for each light source. Decision tree analysis found pack years to be a significant variable for TES. Discussion: All three light sources were comparable with previous studies. The CFL provided better colour discrimination than the LED despite them both being 6500 K. Deuteranomalous trichromats showed a greatest deviation than normal trichromats using the LED. Conclusions: The Kosnic KCF07ALU/GU10-865 is a cost-effective alternative for colour vision testing. Smoking appears to have an effect on colour vision, but requires further investigation

Cognitive Biology: Dealing with Information from Bacteria to Minds

Providing a new conceptual scaffold for further research in biology and cognition, this text introduces the new field of cognitive biology, treating developing organisms as information processors which use cognition to control and modify their environments

Learned Feedback & Feedforward Perception & Control

The notions of feedback and feedforward information processing gained prominence under cybernetics, an early movement at the dawn of computer science and theoretical neuroscience. Negative feedback processing corrects errors, whereas feedforward processing makes predictions, thereby preemptively reducing errors. A key insight of cybernetics was that such processes can be applied to both perception, or state estimation, and control, or action selection. The remnants of this insight are found in many modern areas, including predictive coding in neuroscience and deep latent variable models in machine learning. This thesis draws on feedback and feedforward ideas developed within predictive coding, adapting them to improve machine learning techniques for perception (Part II) and control (Part III). Upon establishing these conceptual connections, in Part IV, we traverse this bridge, from machine learning back to neuroscience, arriving at new perspectives on the correspondences between these fields.</p

Visual perception an information-based approach to understanding biological and artificial vision

The central issues of this dissertation are (a) what should we be doing — what problems should we be trying to solve — in order to build computer vision systems, and (b) what relevance biological vision has to the solution of these problems. The approach taken to tackle these issues centres mostly on the clarification and use of information-based ideas, and an investigation into the nature of the processes underlying perception. The primary objective is to demonstrate that information theory and extensions of it, and measurement theory are powerful tools in helping to find solutions to these problems. The quantitative meaning of information is examined, from its origins in physical theories, through Shannon information theory, Gabor representations and codes towards semantic interpretations of the term. Also the application of information theory to the understanding of the developmental and functional properties of biological visual systems is discussed. This includes a review of the current state of knowledge of the architecture and function of the early visual pathways, particularly the retina, and a discussion of the possible coding functions of cortical neurons. The nature of perception is discussed from a number of points of view: the types and function of explanation of perceptual systems and how these relate to the operation of the system; the role of the observer in describing perceptual functions in other systems or organisms; the status and role of objectivist and representational viewpoints in understanding vision; the philosophical basis of perception; the relationship between pattern recognition and perception, and the interpretation of perception in terms of a theory of measurement These two threads of research, information theory and measurement theory are brought together in an overview and reinterpretation of the cortical role in mammalian vision. Finally the application of some of the coding and recognition concepts to industrial inspection problems are described. The nature of the coding processes used are unusual in that coded images are used as the input for a simple neural network classifier, rather than a heuristic feature set The relationship between the Karhunen-Loève transform and the singular value decomposition is clarified as background the coding technique used to code the images. This coding technique has also been used to code long sequences of moving images to investigate the possibilities of recognition of people on the basis of their gait or posture and this application is briefly described

Activie vision in robot cognition

Tese de doutoramento, Engenharia Informática, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016As technology and our understanding of the human brain evolve, the idea of creating robots that behave and learn like humans seems to get more and more attention. However, although that knowledge and computational power are constantly growing we still have much to learn to be able to create such machines. Nonetheless, that does not mean we cannot try to validate our knowledge by creating biologically inspired models to mimic some of our brain processes and use them for robotics applications. In this thesis several biologically inspired models for vision are presented: a keypoint descriptor based on cortical cell responses that allows to create binary codes which can be used to represent speci c image regions; and a stereo vision model based on cortical cell responses and visual saliency based on color, disparity and motion. Active vision is achieved by combining these vision modules with an attractor dynamics approach for head pan control. Although biologically inspired models are usually very heavy in terms of processing power, these models were designed to be lightweight so that they can be tested for real-time robot navigation, object recognition and vision steering. The developed vision modules were tested on a child-sized robot, which uses only visual information to navigate, to detect obstacles and to recognize objects in real time. The biologically inspired visual system is integrated with a cognitive architecture, which combines vision with short- and long-term memory for simultaneous localization and mapping (SLAM). Motor control for navigation is also done using attractor dynamics

Distributed multimedia quality: The user perspective

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Distributed multimedia supports a symbiotic infotainment duality, i.e. the ability to transfer information to the user, yet also provide the user with a level of satisfaction. As multimedia is ultimately produced for the education and / or enjoyment of viewers, the user’s-perspective concerning the presentation quality is surely of equal importance as objective Quality of Service (QoS) technical parameters, to defining distributed multimedia quality. In order to extensively measure the user-perspective of multimedia video quality, we introduce an extended model of distributed multimedia quality that segregates quality into three discrete levels: the network-level, the media-level and content-level, using two distinct quality perspectives: the user-perspective and the technical-perspective. Since experimental questionnaires do not provide continuous monitoring of user attention, eye tracking was used in our study in order to provide a better understanding of the role that the human element plays in the reception, analysis and synthesis of multimedia data. Results showed that video content adaptation, results in disparity in user video eye-paths when: i) no single / obvious point of focus exists; or ii) when the point of attention changes dramatically. Accordingly, appropriate technical- and user-perspective parameter adaptation is implemented, for all quality abstractions of our model, i.e. network-level (via simulated delay and jitter), media-level (via a technical- and user-perspective manipulated region-of-interest attentive display) and content-level (via display-type and video clip-type). Our work has shown that user perception of distributed multimedia quality cannot be achieved by means of purely technical-perspective QoS parameter adaptation

Internal outset:Exploring empirical and philosophical implications of the free-energy principle

The present dissertation took the free-energy principle (FEP) as its starting point, from which we tried to draw both philosophical and empirical consequences. Both chapter 2 and 3 departed from the idea that conscious perception depends on global amplification of sensory input, and that the basal ganglia (BG) and its irrigation by dopamine play a crucial role in gating information, conscious access, and the selection of a relevant internal model given available sensory data. The BG are thought to play this role due to their modulatory influence on thalamocortical connectivity. Because much of the evidence implicating the BG in these processes in humans is correlational, we explored two ways of manipulating BG activity experimentally. Chapter 4 investigates the philosophical heritage implicitly touched on by the FEP, which provides an alternative philosophical and historical background for present-day research in cognitive neuroscience. Friston’s FEP has been received with great enthusiasm. With good reason: it not only makes the bold claim to a unifying theory of the brain, but it is presented as an a priori principle applicable to living systems in general. In this paper, we set out to show how the breadth of scope of Friston’s framework converges with the dialectics of Georg Hegel. Through an appeal to the work of Catherine Malabou, we aimed to demonstrate how Friston not only reinvigorates Hegelian dialectics from the perspective of neuroscience, but that the implicit alignment with Hegel necessitates a reading of the FEP from the perspective of Hegel’s speculative philosophy. It is this reading that moves beyond the discussion between cognitivism and enactivism surrounding Friston’s framework; beyond the question whether the organism is a secluded entity separated from its surroundings, or whether it is a dynamical system characterized by perpetual openness and mutual exchange. From a Hegelian perspective, it is the tension between both positions itself that is operative at the level of the organism; as a contradiction the organism sustains over the course of its life. Not only does the organism’s secluded existence depend on a perpetual relation with its surroundings, but the condition for there to be such a relation is the existence of a secluded entity. We intended to show how this contradiction – tension internalized – is at the center of Friston’s anticipatory organism; how it is this contradiction that grounds the perpetual process of free energy minimization. Chapter 5 is the report of a study attempting to contrast the FEP’s perspective with that of traditional cognitive neuroscience. While the FEP casts the brain as an organism’s predictive model of how its world works and will continue to work in the future in which action is afforded a central place, research on the brain’s predictive capacities remains beholden to traditional research practices in which participants are passively shown stimuli without their active involvement (as we also did in Chapters 2 and 3). The current study is an investigation into ways in which self-generated predictions may differ from externally induced predictions. Participants completed a volatile spatial attention task under both conditions (externally/cue-induced, internally/action-induced) on different days. We used the Hierarchical Gaussian Filter, an approximate Bayesian inference model, to determine subject-specific parameters of belief-updating and inferred volatility. We found preliminary evidence in support of self-generated predictions incurring a larger reaction time cost when violated compared to predictions induced by sensory cue, which translated to participants’ increased sensitivity to changes in environmental volatility. Our results suggest that internally generated predictions may be afforded more weight, but these results are complicated by session order and duration effects, as well as a lack of statistical power

Novel photoreceptor cells, pupillometry and electrodiagnosis in orbital, vitreo-retinal and refractive disorders

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Inhomogeneity of visual space, discontinuity of perceptual time and cultural imprinting as exemplified with experiments on visual attention, aesthetic appreciation and temporal processing

Eines der wichtigsten Argumente für einen kognitivistischen Zugang zur Psychologie ist, dass sich die Psychologie nicht grundlegend von der Physik zu unterscheiden scheint; mentale Phänomene sind offenbar unmittelbar auf physikalische Realität bezogen. Beginnend mit der Psychophysik seit dem neunzehnten Jahrhunderts haben Experimente gezeigt, dass dieser Denkansatz nicht nur mit großen Vorteilen, sondern auch mit einigen Fallstricken verbunden sein kann. Auf der Basis des zugrundeliegenden Konzepts, dass mentale Phänomene physikalischen Ereignissen unmittelbar zugeordnet werden können, wird automatisch angenommen, dass die zeitliche Verarbeitung von sensorischen Informationen kontinuierlich sei, wie es das Zeitkonzept in der klassischen Physik nahelegt. Dieses Konzept widerspricht der Möglichkeit einer diskreten zeitlichen Informationsverarbeitung, wie sie in der Tat gilt. Des weiteren wird davon ausgegangen, dass Informationsverarbeitung in einem homogenen visuellen Wahrnehmungsraum eingebettet ist; dies ist jedoch nicht der Fall. Es wird dargestellt, dass mit einfachen sensorischen Reizen oder komplexen ästhetischen Stimuli und deren experimenteller Manipulation ein brauchbares empirisches Paradigma für ein besseres Verständnis von kognitiven Mechanismen bereitsteht, das auf diskrete zeitliche Verarbeitung und einen inhomogenen visuellen Wahrnehmungsraum hinweist. In mehreren Experimenten wird gezeigt, daß die Modulation der Aufmerksamkeit im Gesichtsfeld nicht homogen ist; Reaktionszeitexperimente mit spezifischen Modifikationen stützen die Hypothese, dass funktionell zwei Aufmerksamkeitssysteme im Gesichtsfeld eingebettet sind. Weitere unterstützende Beobachtungen über die Inhomogenität des Gesichtsfeldes kommen aus Experimenten zur ästhetischen Wahrnehmung westlicher und östlicher Kunstwerke. Diese Forschung bestätigt überdies das allgemeine Konzept von anthropologischen Universalien sowie kulturellen oder individuellen Spezifika bei der ästhetischen Wahrnehmung. Im Hinblick auf die zeitliche Wahrnehmung weisen Histogramme der Reaktionszeit auf diskrete zeitliche Informationsverarbeitung hin, was sich auch aus Beobachtungen der zeitlichen Ordnungsschwelle herleiten läßt. Bei der Untersuchung verzögerter Reaktionen wird gezeigt, dass eine präzise zeitliche Kontrolle erst nach einem längeren Intervall erreicht wird. Zusammenfassend kann man aus den verschiedenen Experimenten herleiten, dass mentale Prozesse im räumlichen und zeitlichen Bereich zwar offenkundig nicht direkt zugänglich sind, doch sollte dies nicht als eine undurchdringliche Barriere angesehen werden, um Mechanismen mentaler Prozesse zu entschlüsseln. Mit den klar definierten physikalischen Stimuli und der genauen Beachtung von Stationaritätsbedingungen bei Messungen kann diskrete zeitliche Verarbeitung und Inhomogenität des visuellen Wahrnehmungsraums gezeigt werden.One of the most compelling arguments for a cognitivist approach to psychology is that psychology does not seem to be fundamentally different from physics; mental phenomena appear to be directly related to physical reality. Experimental evidence beginning in the nineteenth century with psychophysics has shown that this approach can offer great benefits, but can suffer from some pitfalls as well. On the basis of the underlying concept that mental phenomena match directly physical events, it is automatically assumed that temporal processing of sensory information is continuous as it is assumed in classical physics neglecting the possibility of discrete temporal information processing, which in fact is the case. Furthermore, it is assumed that information processing is embedded in a homogeneous perceptual visual space; this is not the case. It is shown that the use of simple sensory stimuli or complex aesthetic stimuli and their experimental manipulation provide a useful empirical paradigm for a better understanding of the cognitive mechanisms, i.e., indicating discrete temporal processing and an inhomogeneous perceptual visual space. A number of experiments show that attentional modulation is not homogeneous in the visual field; observations using the reaction time paradigm with specific modifications support the hypothesis that two attention systems are functionally embedded in the visual field. Further supportive findings about the inhomogeneity of the visual field come from experiments on the aesthetic perception of Western and Eastern artworks. This research also confirms in addition the general concept of anthropological universals and cultural or individual specifics in aesthetic appreciation. With regard to temporal perception, reaction time distributions suggest discrete time sampling which can also be derived from observations on temporal order threshold. When testing delayed reactions after stimulus presentation, it is shown that precise temporal control is reached only after a rather long interval. It can be concluded on the basis of the different experiments that even though mental processes in the space and time domain are obviously not directly accessible, this should not be considered as an impenetrable barrier to unravel the mechanism of mental processes. Employing well-defined physical stimuli and strictly observing stationarity conditions in measurements indicate discreteness in temporal processing and inhomogeneity of visual space