Academic literature on the topic 'Continuously self-imaging objects'

This paper describes a novel optical system that can be integrated to the image port of an existing brightfield microscope in order to enhance the microscope with the features of digital holographic microscopy. The proposed system is modular and portable. It is relatively inexpensive and robust to vibrations due to its compact design. An additional benefit is that the system does not need to undergo path-length realignment if the sample is changed, unlike several other architectures. The module is based on a square in-line Mach–Zender architecture but achieves the off-axis condition using two sets of wedge prism pairs. This design offers a significant advantage over competing Mach–Zender nearly common-path modules in terms of path length matching of object and reference wavefields for the case of low-temporal coherence sources, which are preferable for low noise phase imaging. An additional advantage that the proposed system has when compared with similar modules is the facility to continuously vary the tilt angles of the object and reference wavefields that are incident on the sensor, which enables the module to be readily adapted to any given microscope and camera. We provide a detailed overview of the module design and construction. Experimental results are demonstrated on a micro-lens array as well as buccal epithelial cells. We also provide a detailed discussion on the relationship between the proposed self-reference module and related common-path and nearly common-path holographic modules that have previously been proposed in the literature.

Wearable electronics have been receiving increasing attention for the past few decades. Particularly, fiber-based electronics are considered to be ideal for many applications for their flexibility, lightweight, breathability, and comfortability. Furthermore, fibers and fiber-based textiles can be 3D-molded with ease and potentially integrated with everyday clothes or accessories. These properties are especially desired in the fields of bio-related sensors and energy-storage systems. Wearable sensors utilize a tight interface with human skin and clothes for continuous environmental scanning and non-invasive health monitoring. At the same time, their flexible and lightweight properties allow more convenient and user-friendly experiences to the wearers. Similarly, for the wearable devices to be more accessible, it is crucial to incorporate energy harvesting and storage systems into the device themselves, removing the need to attach an external power source. This review summarizes the recent applications of fibers and fiber-based textiles in mechanical, photonic, and biomedical sensors. Pressure and strain sensors and their implementation as electronic skins will be explored, along with other various fiber sensors capable of imaging objects or monitoring safety and health markers. In addition, we attempt to elucidate recent studies in energy-storing fibers and their implication in self-powered and fully wireless wearable devices.

Wearable electronics have been receiving increasing attention for the past few decades. Particularly, fiber-based electronics are considered to be ideal for many applications for their flexibility, lightweight, breathability, and comfortability. Furthermore, fibers and fiber-based textiles can be 3D-molded with ease and potentially integrated with everyday clothes or accessories. These properties are especially desired in the fields of bio-related sensors and energy-storage systems. Wearable sensors utilize a tight interface with human skin and clothes for continuous environmental scanning and non-invasive health monitoring. At the same time, their flexible and lightweight properties allow more convenient and user-friendly experiences to the wearers. Similarly, for the wearable devices to be more accessible, it is crucial to incorporate energy harvesting and storage systems into the device themselves, removing the need to attach an external power source. This review summarizes the recent applications of fibers and fiber-based textiles in mechanical, photonic, and biomedical sensors. Pressure and strain sensors and their implementation as electronic skins will be explored, along with other various fiber sensors capable of imaging objects or monitoring safety and health markers. In addition, we attempt to elucidate recent studies in energy-storing fibers and their implication in self-powered and fully wireless wearable devices.

We study experimentally the spatial distribution, settling and interaction of sub-Kolmogorov inertial particles with homogeneous turbulence. Utilizing a zero-mean-flow air turbulence chamber, we drop size-selected solid particles and study their dynamics with particle imaging and tracking velocimetry at multiple resolutions. The carrier flow is simultaneously measured by particle image velocimetry of suspended tracers, allowing the characterization of the interplay between both the dispersed and continuous phases. The turbulence Reynolds number based on the Taylor microscale ranges from $Re_{\unicode[STIX]{x1D706}}\approx 200{-}500$, while the particle Stokes number based on the Kolmogorov scale varies between $St_{\unicode[STIX]{x1D702}}=O(1)$ and $O(10)$. Clustering is confirmed to be most intense for $St_{\unicode[STIX]{x1D702}}\approx 1$, but it extends over larger scales for heavier particles. Individual clusters form a hierarchy of self-similar, fractal-like objects, preferentially aligned with gravity and with sizes that can reach the integral scale of the turbulence. Remarkably, the settling velocity of $St_{\unicode[STIX]{x1D702}}\approx 1$ particles can be several times larger than the still-air terminal velocity, and the clusters can fall even faster. This is caused by downward fluid fluctuations preferentially sweeping the particles, and we propose that this mechanism is influenced by both large and small scales of the turbulence. The particle–fluid slip velocities show large variance, and both the instantaneous particle Reynolds number and drag coefficient can greatly differ from their nominal values. Finally, for sufficient loadings, the particles generally augment the small-scale fluid velocity fluctuations, which however may account for a limited fraction of the turbulent kinetic energy.

This article provides the review of the medical use of pH- and temperature-sensitive polymer hydrogels. Such polymers are characterised by their thermal and pH sensitivity in aqueous solutions at the functioning temperature of living organisms and can react to the slightest changes in environmental conditions. Due to these properties, they are called stimuli-sensitive polymers. This response to an external stimulus occurs due to the amphiphilicity (diphilicity) of these (co)polymers. The term hydrogels includes several concepts of macrogels and microgels. Microgels, unlike macrogels, are polymer particles dispersed in a liquid and are nano- or micro-objects. The review presents studies reflecting the main methods of obtainingsuch polymeric materials, including precipitation polymerisation, as the main, simplest, and most accessible method for mini-emulsion polymerisation, microfluidics, and layer-by-layer adsorption of polyelectrolytes. Such systems will undoubtedly be promising for use in biotechnology and medicine due to the fact that they are liquid-swollen particles capable of binding and carrying various low to high molecular weight substances. It is also important that slight heating and cooling or a slight change in the pH of the medium shifts the system from a homogeneous to a heterogeneous state and vice versa. This providesthe opportunity to use these polymers as a means of targeted drug delivery, thereby reducing the negative effect of toxic substances used for treatment on the entire body and directing the action to a specific point. In addition, such polymers can be used to create smart coatings of implanted materials, as well as an artificial matrix for cell and tissue regeneration, contributing to a significant increase in the survival rate and regeneration rate of cells and tissues. References 1. Gisser K. R. C., Geselbracht M. J., Cappellari A.,Hunsberger L., Ellis A. B., Perepezko J., et al. 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Whichever way you look at it, self is bound up with consciousness, so it seems useful to review some of the more significant existing conceptions of this relationship. A claim by Mikhail Bakhtin can serve as an anchoring point for this discussion. He firmly predicates the formation of self not just on the existence of an individual consciousness, but on what might be called a double or social (or dialogic) consciousness. Summarising his argument, Pam Morris writes: 'A single consciousness could not generate a sense of its self; only the awareness of another consciousness outside the self can produce that image.' She goes on to say that, 'Behind this notion is Bakhtin's very strong sense of the physical and spatial materiality of bodily being,' and quotes directly from Bakhtin's essay as follows: This other human being whom I am contemplating, I shall always see and know something that he, from his place outside and over against me, cannot see himself: parts of his body that are inaccessible to his own gaze (his head, his face and its expression), the world behind his back . . . are accessible to me but not to him. As we gaze at each other, two different worlds are reflected in the pupils of our eyes . . . to annihilate this difference completely, it would be necessary to merge into one, to become one and the same person. This ever--present excess of my seeing, knowing and possessing in relation to any other human being, is founded in the uniqueness and irreplaceability of my place in the world. (Bakhtin in Morris 6 Recent investigations in neuroscience and the philosophy of mind lay down a challenge to this social conception of the self. Notably, it is a challenge that does not involve the restoration of any variant of Cartesian rationalism; indeed, it arguably over--privileges rationalism's subjective or phenomenological opposite. 'Self' in this emerging view is a biologically generated but illusory construction, an effect of the operation of what are called 'neural correlates of consciousness' (NCC). Very briefly, an NCC refers to the distinct pattern of neurochemical activity, a 'neural representational system' -- to some extent observable by modern brain--imaging equipment – that corresponds to a particular configuration of sense--phenomena, or 'content of consciousness' (a visual image, a feeling, or indeed a sense of self). Because this science is still largely hypothetical, with many alternative terms and descriptions, it would be better in this limited space to focus on one particular account – one that is particularly well developed in the area of selfhood and one that resonates with other conceptions included in this discussion. Thomas Metzinger begins by postulating the existence within each person (or 'system' in his terms) of a 'self--model', a representation produced by neural activity -- what he calls a 'neural correlate of self--consciousness' -- that the individual takes to be the actual self, or what Metzinger calls the 'phenomenal self'. 'A self--model is important,' Metzinger says, 'in enabling a system to represent itself to itself as an agent' (293). The individual is able to maintain this illusion because 'the self--model is the only representational structure that is anchored in the brain by a continuous source of internally generated input' (297). In a manner partly reminiscent of Bakhtin, he continues: 'The body is always there, and although its relational properties in space and in movement constantly change, the body is the only coherent perceptual object that constantly generates input.' The reason why the individual is able to jump from the self--model to the phenomenal self in the first place is because: We are systems that are not able to recognise their subsymbolic self--model as a model. For this reason, we are permanently operating under the conditions of a 'naïve--realistic self--misunderstanding': We experience ourselves as being in direct and immediate epistemic contact with ourselves. What we have in the past simply called a 'self' is not a non--physical individual, but only the content of an ongoing dynamical process – the process of transparent self—modeling. (Metzinger 299) The question that nonetheless arises is why it should be concluded that this self--model emerges from subjective neural activity and not, say, from socialisation. Why should a self--model be needed in the first place? Metzinger's response is to say that there is good evidence 'for some kind of innate 'body prototype'' (298), and he refers to research that shows that even children born without limbs develop self--models which sometimes include limbs, or report phantom sensations in limbs that have never existed. To me, this still leaves open the possibility that such children are modelling their body image on strong identification with human others. But be that as it may, one of the things that remains unclear after this relatively rich account of contemporary or scientific phenomenology is the extent to which 'neural consciousness' is or can be supplemented by other kinds of consciousness, or indeed whether neural consciousness can be overridden by the 'self' acting on the basis of these other kinds of consciousness. The key stake in Metzinger's account is 'subjectivity'. The reason why the neural correlate of self--consciousness is so important to him is: 'Only if we find the neural and functional correlates of the phenomenal self will we be able to discover a more general theoretical framework into which all data can fit. Only then will we have a chance to understand what we are actually talking about when we say that phenomenal experience is a subjective phenomenon' (301). What other kinds of consciousness might there be? It is significant that, not only do NCC exponents have little to say about the interaction with other people, they rarely mention language, and they are unanimously and emphatically of the opinion that the thinking or processing that takes place in consciousness is not dependent on language, or indeed any signifying system that we know of (though conceivably, it occurs to me, the neural correlates may signify to, or 'call up', each other). And they show little 'consciousness' that a still influential body of opinion (informed latterly by post--structuralist thinking) has argued for the consciousness shaping effects of 'discourse' -- i.e. for socially and culturally generated patterns of language or other signification to order the processing of reality. We could usefully coin the term 'verbal correlates of consciousness' (VCC) to refer to these patterns of signification (words, proverbs, narratives, discourses). Again, however, the same sorts of questions apply, since few discourse theorists mention anything like neuroscience: To what extent is verbal consciousness supplemented by other forms of consciousness, including neural consciousness? These questions may never be fully answerable. However, it is interesting to work through the idea that NCC and VCC both exist and can be in some kind of relation even if the precise relationship is not measurable. This indeed is close to the case that Charles Shepherdson makes for psychoanalysis in attempting to retrieve it from the misunderstanding under which it suffers today: We are now familiar with debates between those who seek to demonstrate the biological foundations of consciousness and sexuality, and those who argue for the cultural construction of subjectivity, insisting that human life has no automatically natural form, but is always decisively shaped by contingent historical conditions. No theoretical alternative is more widely publicised than this, or more heavily invested today. And yet, this very debate, in which 'nature' and 'culture' are opposed to one another, amounts to a distortion of psychoanalysis, an interpretive framework that not only obscures its basic concepts, but erodes the very field of psychoanalysis as a theoretically distinct formation (2--3). There is not room here for an adequate account of Shepherdson's recuperation of psychoanalytic categories. A glimpse of the stakes involved is provided by Shepherdson's account, following Eugenie Lemoine--Luccione, of anorexia, which neither biomedical knowledge nor social constructionism can adequately explain. The further fact that anorexia is more common among women of the same family than in the general population, and among women rather than men, but in neither case exclusively so, thereby tending to rule out a genetic factor, allows Shepherdson to argue: [A]norexia can be understood in terms of the mother--daughter relation: it is thus a symbolic inheritance, a particular relation to the 'symbolic order', that is transmitted from one generation to another . . . we may add that this relation to the 'symbolic order' [which in psychoanalytic theory is not coextensive with language] is bound up with the symbolisation of sexual difference. One begins to see from this that the term 'sexual difference' is not used biologically, but also that it does not refer to general social representations of 'gender,' since it concerns a more particular formation of the 'subject' (12). An intriguing, and related, possibility, suggested by Foucault, is that NCC and VCC (or in Foucault's terms the 'visible' and the 'articulable'), operate independently of each other – that there is a 'disjunction' (Deleuze 64) or 'dislocation' (Shepherdson 166) between them that prevents any dialectical relation. Clearly, for Foucault, the lack of dialectical relation between the two modes does not mean that both are not at all times equally functional. But one can certainly speculate that, increasingly under postmodernity and media saturation, the verbal (i.e. the domain of signification in general) is influential. And if linguistic formations -- discourses, narratives, etc. -- can proliferate and feed on each other unconstrained by other aspects of reality, we get the sense of language 'running away with itself' and, at least for a time, becoming divorced from a more complete sense of reality. (This of course is basically the argument of Baudrillard.) The reverse may also be possible, in certain periods, although the idea that language could have no mediating effect at all on the production of reality (just inconsequential fluff on the surface of things) seems far--fetched in the wake of so much postmodern and media theory. However, the notion is consistent with the theories of hard--line materialists and genetic determinists. But we should at least consider the possibility that some sort of shaping interaction between NCC and VCC, without implicating the full conceptual apparatus of psychoanalysis, is continuously occurring. This possibility is, for me, best realised by Jacques Derrida when he writes of an irreducible interweaving of consciousness and language (the latter for Derrida being a cover term for any system of signification). This interweaving is such that the significatory superstructure 'reacts upon' the 'substratum of non--expressive acts and contents', and the name for this interweaving is 'text' (Mowitt 98). A further possibility is that provided by Pierre Bourdieu's notion of habitus -- the socially inherited schemes of perception and selection, imparted by language and example, which operate for the most part below the level of consciousness but are available to conscious reflection by any individual lucky enough to learn how to recognise that possibility. If the subjective representations of NCC exist, this habitus can be at best only partial; something denied by Bourdieu whose theory of individual agency is founded in what he has referred to as 'the relation between two states of the social' – i.e. 'between history objectified in things, in the form of institutions, and history incarnate in the body, in the form of that system of durable dispositions I call habitus' (190). At the same time, much of Bourdieu's thinking about the habitus seems as though it could be consistent with the kind of predictable representations that might be produced by NCC. For example, there are the simple oppositions that structure much perception in Bourdieu's account. These range from the obvious phenomenological ones (dark/light; bright/dull; male/female; hard/soft, etc.) through to the more abstract, often analogical or metaphorical ones, such as those produced by teachers when assessing their students (bright/dull again; elegant/clumsy, etc.). It seems possible that NCC could provide the mechanism or realisation for the representation, storage, and reactivation of impressions constituting a social model--self. However, an entirely different possibility remains to be considered – which perhaps Bourdieu is also getting at – involving a radical rejection of both NCC and VCC. Any correlational or representational theory of the relationship between a self and his/her environment -- which, according to Charles Altieri, includes the anti--logocentrism of Derrida -- assumes that the primary focus for any consciousness is the mapping and remapping of this relationship rather than the actions and purposes of the agent in question. Referring to the later philosophy of Wittgenstein, Altieri argues: 'Conciousness is essentially not a way of relating to objects but of relating to actions we learn to perform . . . We do not usually think about objects, but about the specific form of activity which involves us with these objects at this time' (233). Clearly, there is not yet any certainty in the arguments provided by neuroscience that neural activity performs a representational role. Is it not, then, possible that this activity, rather than being a 'correlate' of entities, is an accompaniment to, a registration of, action that the rest of the body is performing? In this view, self is an enactment, an expression (including but not restricted to language), and what self--consciousness is conscious of is this activity of the self, not the self as entity. In a way that again returns us towards Bakhtin, Altieri writes: '>From an analytical perspective, it seems likely that our normal ways of acting in the world provide all the criteria we need for a sense of identity. As Sidney Shoemaker has shown, the most important source of the sense of our identity is the way we use the spatio--temporal location of our body to make physical distinctions between here and there, in front and behind, and so on' (234). Reasonably consistent with the Wittgensteinian view -- in its focus on self--activity -- is that contemporary theorisation of the self that compares in influence with that posed by neuroscience. This is the self avowedly constructed by networked computer technology, as described by Mark Poster: [W]hat has occurred in the advanced industrial societies with increasing rapidity . . . is the dissemination of technologies of symbolisation, or language machines, a process that may be described as the electronic textualisation of daily life, and the concomitant transformations of agency, transformations of the constitution of individuals as fixed identities (autonomous, self--regulating, independent) into subjects that are multiple, diffuse, fragmentary. The old (modern) agent worked with machines on natural materials to form commodities, lived near other workers and kin in urban communities, walked to work or traveled by public transport, and read newspapers but engaged as a communicator mostly in face--to--face relations. The new (postmodern) agent works mostly on symbols using computers, lives in isolation from other workers and kin, travels to work by car, and receives news and entertainment from television. . . . Individuals who have this experience do not stand outside the world of objects, observing, exercising rational faculties and maintaining a stable character. The individuals constituted by the new modes of information are immersed and dispersed in textualised practices where grounds are less important than moves. (44--45) Interestingly, Metzinger's theorisation of the model--self lends itself to the self--mutability -- though not the diffusion -- favoured by postmodernists like Poster. [I]t is . . . well conceivable that a system generates a number of different self--models which are functionally incompatible, and therefore modularised. They nevertheless could be internally coherent, each endowed with its own characteristic phenomenal content and behavioral profile. . . this does not have to be a pathological situation. Operating under different self--models in different situational contexts may be biologically as well as socially adaptive. Don't we all to some extent use multiple personalities to cope efficiently with different parts of our lives? (295--6) Poster's proposition is consistent with that of many in the humanities and social sciences today, influenced variously by postmodernism and social constructionism. What I believe remains at issue about his account is that it exchanges one form of externally constituted self ('fixed identity') for another (that produced by the 'modes of information'), and therefore remains locked in a logic of deterministic constitution. (There is a parallel here with Altieri's point about Derrida's inability to escape representation.) Furthermore, theorists like Poster may be too quickly generalising from the experience of adults in 'textualised environments'. Until such time as human beings are born directly into virtual reality environments, each will, for a formative period of time, experience the world in the way described by Bakhtin – through 'a unified perception of bodily and personal being . . . characterised . . . as a loving gift mutually exchanged between self and other across the borderzone of their two consciousnesses' (cited in Morris 6). I suggest it is very unlikely that this emergent sense of being can ever be completely erased even when people subsequently encounter each other in electronic networked environments. It is clearly not the role of a brief survey like this to attempt any resolution of these matters. Indeed, my review has made all the more apparent how far from being settled the question of consciousness, and by extension the question of selfhood, remains. Even the classical notion of the homunculus (the 'little inner man' or the 'ghost in the machine') has been put back into play with Francis Crick and Christof Koch's (2000) neurobiological conception of the 'unconscious homunculus'. The balance of contemporary evidence and argument suggests that the best thing to do right now is to keep the questions open against any form of reductionism – whether social or biological. One way to do this is to explore the notions of self and consciousness as implicated in ongoing processes of complex co--adaptation between biology and culture -- or their individual level equivalents, brain and mind (Taylor Ch. 7). References Altieri, C. "Wittgenstein on Consciousness and Language: a Challenge to Derridean Literary Theory." Wittgenstein, Theory and the Arts. Ed. Richard Allen and Malcolm Turvey. New York: Routledge, 2001. Bourdieu, P. In Other Words: Essays Towards a Reflexive Sociology. Trans. Matthew Adamson. Stanford: Stanford University Press, 1990. Crick, F. and Koch, C. "The Unconscious Homunculus." Neural Correlates of Consciousness: Empirical and Conceptual Questions. Ed. Thomas Metzinger. Cambridge, Mass.: MIT Press, 2000. Deleuze, G. Foucault. Trans. Sean Hand. Minneapolis: University of Minnesota Press, 1988. Metzinger, T. "The Subjectivity of Subjective Experience: A Representationalist Analysis of the First-Person Perspective." Neural Correlates of Consciousness: Empirical and Conceptual Questions. Ed. Thomas Metzinger. Cambridge, Mass.: MIT Press, 2000. Morris, P. (ed.). The Bakhtin Reader: Selected Writings of Bakhtin, Medvedev, Voloshinov. London: Edward Arnold, 1994. Mowitt, J. Text: The Genealogy of an Interdisciplinary Object. Durham: Duke University Press, 1992. Poster, M. Cultural History and Modernity: Disciplinary Readings and Challenges. New York: Columbia University Press, 1997. Shepherdson, C. Vital Signs: Nature, Culture, Psychoanalysis. New York: Routledge, 2000. Taylor, M. C. The Moment of Complexity: Emerging Network Culture. Chicago: University of Chicago Press, 2001. Citation reference for this article Substitute your date of access for Dn Month Year etc... MLA Style Wallace, Derek. "'Self' and the Problem of Consciousness" M/C: A Journal of Media and Culture 5.5 (2002). [your date of access] < http://www.media-culture.org.au/mc/0210/Wallace.html &gt. Chicago Style Wallace, Derek, "'Self' and the Problem of Consciousness" M/C: A Journal of Media and Culture 5, no. 5 (2002), < http://www.media-culture.org.au/mc/0210/Wallace.html &gt ([your date of access]). APA Style Wallace, Derek. (2002) 'Self' and the Problem of Consciousness. M/C: A Journal of Media and Culture 5(5). < http://www.media-culture.org.au/mc/0210/Wallace.html &gt ([your date of access]).

Abstract While brain imaging tools like functional magnetic resonance imaging (fMRI) afford measurements of whole-brain activity, it remains unclear how best to interpret patterns found amid the data’s apparent self-organization. To clarify how patterns of brain activity support brain function, one might identify metric spaces that optimally distinguish brain states across experimentally defined conditions. Therefore, the present study considers the relative capacities of several metric spaces to disambiguate experimentally defined brain states. One fundamental metric space interprets fMRI data topographically, that is, as the vector of amplitudes of a multivariate signal, changing with time. Another perspective compares the brain’s functional connectivity, that is, the similarity matrix computed between signals from different brain regions. More recently, metric spaces that consider the data’s topology have become available. Such methods treat data as a sample drawn from an abstract geometric object. To recover the structure of that object, topological data analysis detects features that are invariant under continuous deformations (such as coordinate rotation and nodal misalignment). Moreover, the methods explicitly consider features that persist across multiple geometric scales. While, certainly, there are strengths and weaknesses of each brain dynamics metric space, wefind that those that track topological features optimally distinguish experimentally defined brain states.

During aesthetically appealing visual experiences, visual content provides a basis for computation of affectively tinged representations of aesthetic value. How this happens in the brain is largely unexplored. Using engaging video clips of natural landscapes, we tested whether cortical regions that respond to perceptual aspects of an environment (e.g., spatial layout, object content and motion) were directly modulated by rated aesthetic appeal. Twenty-four participants watched a series of videos of natural landscapes while being scanned using functional magnetic resonance imaging (fMRI) and reported both continuous ratings of enjoyment (during the videos) and overall aesthetic judgments (after each video). Although landscape videos engaged a greater expanse of high-level visual cortex compared to that observed for images of landscapes, independently localized category-selective visual regions (e.g., scene-selective parahippocampal place area and motion-selective hMT+) were not significantly modulated by aesthetic appeal. Rather, a whole-brain analysis revealed modulations by aesthetic appeal in ventral (collateral sulcus) and lateral (middle occipital sulcus, posterior middle temporal gyrus) clusters that were adjacent to scene and motion selective regions. These findings suggest that aesthetic appeal per se is not represented in well-characterized feature- and category-selective regions of visual cortex. Rather, we propose that the observed activations reflect a local transformation from a feature-based visual representation to a representation of “elemental affect,” computed through information-processing mechanisms that detect deviations from an observer’s expectations. Furthermore, we found modulation by aesthetic appeal in subcortical reward structures but not in regions of the default-mode network (DMN) nor orbitofrontal cortex, and only weak evidence for associated changes in functional connectivity. In contrast to other visual aesthetic domains, aesthetically appealing interactions with natural landscapes may rely more heavily on comparisons between ongoing stimulation and well-formed representations of the natural world, and less on top-down processes for resolving ambiguities or assessing self-relevance.

La capacité actuelle d’accéder à des détecteurs très performants et de faible coût amène la communauté des concepteurs de systèmes optiques à un changement de paradigme. Plutôt que de réaliser des caméras généralistes, aptes à réaliser un grand nombre de missions d’observation différentes, il est maintenant de plus en plus courant de développer des systèmes imageurs adaptés à une seule mission et/ou à une seule classe d’objets. Prendre en compte ces connaissances a priori sur la scène et la mission, au moment de la conception, permet d’envisager des systèmes plus simples, mais aussi dotés de nouvelles compétences. L'objectif de la thèse est d'explorer les potentialités des tableaux non diffractants pour la conception de systèmes imageurs spécialisés. Pour cette étude nous considérons l'environnement des drones aéroportés de faible capacité d'emport pour lesquels les systèmes imageurs embarqués doivent être simples et robustes. Nous considérons de plus que la mission du système imageur est de détecter les obstacles. Pour cela, il doit délivrer une information 3D sur la scène observée. Dans un premier temps, j'ai analysé les propriétés d'imagerie du système imageur constitué d'un composant non diffractant et d'un détecteur matriciel. L'analyse comparative de deux composants, l'axicon et le tableau non diffractant, m'a permis de montrer que c'est le second composant qui est le mieux adapté pour remplir ce type de mission. J'ai ensuite réalisé un système imageur de démonstration, ce qui m'a permis au final de mettre en évidence sa capacité à faire de l'imagerie 3D. Cette étude a montré que les tableaux non diffractants ont un très fort potentiel pour réaliser un système imageur simple, robuste et dédié à l'imagerie 3D. Ce travail doit être poursuivi en partenariat avec des industriels pour appliquer la démarche de conception à une mission précise et transformer ce travail théorique en un système industrialisable
Currently, detectors with high performances and a low cost are available and lead the community of optical designers to a new paradigm. Instead of designing generalist cameras, suitable for fulfilling a high number of different observation missions, it is now more and more common to develop imaging systems adapted to a unique mission and/or a unique object class. Taking this a priori knowledge on the observed scene or on the mission into account, at the beginning of the design process, allows us to consider simpler imaging systems with new properties. The aim of this thesis is to investigate the possibilities of nondiffracting array for the design of specialized imaging systems. For this study we consider the environment of unmanned aerial vehicles with a small payload capacity, for which embedded imaging systems must be simple and robust. We consider in addition that the mission of the imaging system is to detect obstacles. To do this, it must provide a 3D information on the observed scene. At first, I have analysed the properties of the imaging system composed by a nondiffracting optical device and a focal plane array. The comparison between two devices, axicon and nondiffracting arrays, allowed me to show that the second one is best suited for achieving this kind of mission. Then, I have made a practical implementation of such an imaging system. Finally, I have used it to demonstrate the 3D imaging property. This study has demonstrated the potential of nondiffracting array to design a simple and robust imaging system dedicated to 3D imaging. This work must be continued in partnership with the industry to apply the co-design process to a more precise mission, transforming this way this theoretical work into an industrial prototype