1,240 research outputs found

    Impact of Imaging and Distance Perception in VR Immersive Visual Experience

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    Virtual reality (VR) headsets have evolved to include unprecedented viewing quality. Meanwhile, they have become lightweight, wireless, and low-cost, which has opened to new applications and a much wider audience. VR headsets can now provide users with greater understanding of events and accuracy of observation, making decision-making faster and more effective. However, the spread of immersive technologies has shown a slow take-up, with the adoption of virtual reality limited to a few applications, typically related to entertainment. This reluctance appears to be due to the often-necessary change of operating paradigm and some scepticism towards the "VR advantage". The need therefore arises to evaluate the contribution that a VR system can make to user performance, for example to monitoring and decision-making. This will help system designers understand when immersive technologies can be proposed to replace or complement standard display systems such as a desktop monitor. In parallel to the VR headsets evolution there has been that of 360 cameras, which are now capable to instantly acquire photographs and videos in stereoscopic 3D (S3D) modality, with very high resolutions. 360° images are innately suited to VR headsets, where the captured view can be observed and explored through the natural rotation of the head. Acquired views can even be experienced and navigated from the inside as they are captured. The combination of omnidirectional images and VR headsets has opened to a new way of creating immersive visual representations. We call it: photo-based VR. This represents a new methodology that combines traditional model-based rendering with high-quality omnidirectional texture-mapping. Photo-based VR is particularly suitable for applications related to remote visits and realistic scene reconstruction, useful for monitoring and surveillance systems, control panels and operator training. The presented PhD study investigates the potential of photo-based VR representations. It starts by evaluating the role of immersion and user’s performance in today's graphical visual experience, to then use it as a reference to develop and evaluate new photo-based VR solutions. With the current literature on photo-based VR experience and associated user performance being very limited, this study builds new knowledge from the proposed assessments. We conduct five user studies on a few representative applications examining how visual representations can be affected by system factors (camera and display related) and how it can influence human factors (such as realism, presence, and emotions). Particular attention is paid to realistic depth perception, to support which we develop target solutions for photo-based VR. They are intended to provide users with a correct perception of space dimension and objects size. We call it: true-dimensional visualization. The presented work contributes to unexplored fields including photo-based VR and true-dimensional visualization, offering immersive system designers a thorough comprehension of the benefits, potential, and type of applications in which these new methods can make the difference. This thesis manuscript and its findings have been partly presented in scientific publications. In particular, five conference papers on Springer and the IEEE symposia, [1], [2], [3], [4], [5], and one journal article in an IEEE periodical [6], have been published

    Characterising feedback to mid-level visual cortex during perceptual decision-making

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    A long-standing question in neuroscience is how the activity of visual neurons supports perception. Historically examined from a purely feedforward perspective, this approach documented neuronal selectivity for specific perceptual features, sensitivity akin to an animal’s perceptual sensitivity and demonstrated causal effects of sensory neurons on an animal’s decision. Indeed, even the variable activity of single sensory neurons was found to be correlated with the decision an animal would make, often referred to as ‘choice probability’. This decision-related activity was long interpreted as reflecting the causal effect of feedforward noise on the decision process, but increasing evidence has pointed to a feedback origin of these correlations with behaviour. However the role of that such feedback remains unclear. The work in this thesis sought to investigate the nature of this feedback in order to help explain what it’s potential role in perceptual-decision making may be, as well as to further clarify long-held beliefs on the origin of decision-related activity. To do so, we focussed on the mechanisms underlying disparity perception in disparity-selective mid-level visual areas. First, we tested whether neurons in area V2 were causally involved in a disparity discrimination task. By electrically stimulating disparity-selective V2 neurons, we demonstrated a bias in the animals’ decisions in line with the preference of the stimulated neurons, suggesting a causal role for these neurons in disparity perception. We then proceeded to better characterise the feedback that gives rise to decision-related activity in these neurons, as well as another group of disparity-selective neurons in V3/V3a. Since feedback has often been assumed to selectively target visual neurons based on their relevance for the task or stimulus demands, we aimed to test the extent of this selectivity. To do so, we employed a novel task combining disparity discrimination with a spatial attention component, wherein animals had to ignore one stimulus whilst discriminating the other. Critically, this led to distinct predictions for decision-related activity depending on how selective the feedback would be. We found that decision-related activity could be observed for neurons representing an ignored task-irrelevant stimulus, incompatible with accounts of feedback which exclusively target task-relevant neurons. Our findings suggest that decision-related activity arises predominantly as a result of feedback targeting neurons selective for disparity, regardless of whether they contribute to the task. Importantly they imply a biological constraint to the selectivity of feedback, and demand a revision of current theoretical accounts of feedback in perceptual decision-making. The work presented here thus not only contributes to our understanding of disparity perception, but has critical implications for how feedback modulates the responses of visual neurons and ultimately shapes perception

    Future developments in ground-based gamma-ray astronomy

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    Ground-based gamma-ray astronomy is a powerful tool to study cosmic-ray physics, providing a diagnostic of the high-energy processes at work in the most extreme astrophysical accelerators of the universe. Ground-based gamma-ray detectors apply a number of experimental techniques to measure the products of air showers induced by the primary gamma-rays over a wide energy range, from about 30 GeV to few PeV. These are based either on the measurement of the atmospheric Cherenkov light induced by the air showers, or the direct detection of the shower's secondary particles at ground level. Thanks to the recent development of new and highly sensitive ground-based gamma-ray detectors, important scientific results are emerging which motivate new experimental proposals, at various stages of implementation. In this chapter we will present the current expectations for future experiments in the field.Comment: To appear in "Handbook of X-ray and Gamma-ray Astrophysics" by Springer (Eds. C. Bambi and A. Santangelo) - 59 p

    A philosophical discussion of the implications and limitations of using Virtual Reality Technology (VR) as an “Empathy Machine”

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    This thesis engages in a philosophical discussion on “empathy”, “virtuality”, and the use of virtual reality (VR) technology as an “empathy machine”. Here, I define empathy as the intentional activity (or skill) of recreating aspects of another subject’s emotional experience in one’s imagination to reflectively and “experientially” understand what another is feeling. As opposed to isomorphically appropriating another’s feelings to oneself, I identify empathy as third-personally “feeling with” others. After exploring the narrow and pluralistic approaches to understanding empathy, I argue that there are compelling pragmatic reasons for adopting the pluralistic approach, the proponents of which prefer to highlight varieties of empathy instead of a sole conceptualisation of “empathy proper”. As for virtuality, I subscribe to a third view that can be located between “virtual realism” and “virtual irrealism”, in that I understand virtuality as a sui generis mode of technological actualisation, where psychophysiological illusions, of virtual presence and embodiment, coexist with veridical elements, such as virtual social objects, without causing a defect in users’ rational judgment. My main contention in this research is that VR’s multisensory affordances can be instrumentally utilised as a complementary extension (but never as a replacement) for offsetting some of the limitations in attaining interpersonal empathy through imaginative perspective-taking alone. After discussing this contention in more depth, I then attempt to address some of the recurrent challenges and criticism raised against VR’s use as an empathy machine. Finally, I highlight some of the limitations in VR technology’s capability to capture and transmit a full representation of others’ lived experiences

    Complicated objects: artifacts from the Yuanming Yuan in Victorian Britain

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    The 1860 spoliation of the Summer Palace at the close of the Second Opium War by British and French troops was a watershed event within the development of Britain as an imperialist nation, which guaranteed a market for opium produced in its colony India and demonstrated the power of its armed forces. The distribution of the spoils to officers and diplomatic corps by campaign leaders in Beijing was also a sign of the British Army’s rising power as an instrument of the imperialist state. These conditions would suggest that objects looted from the site would be integrated into an imperialist aesthetic that reflected and promoted the material benefits of military engagement overseas and foregrounded the circumstances of their removal to Britain for campaign members and the British public. This study mines sources dating to the two decades following the war – including British newspapers, auction house records, exhibition catalogs and works of art – to test this hypothesis. Findings show that initial movements of looted objects through the military and diplomatic corps did reinforce notions of imperialist power by enabling campaign members to profit from the spoliation through sales of looted objects and trophy displays. However, material from the Summer Palace arrived at a moment when British manufacturers and cultural leaders were engaged in a national effort to improve the quality of British goods to compete in the international marketplace and looted art was quickly interpolated in this national conversation. Ironically, the same “free trade” imperatives that motivated the invasion energized a new design movement that embraced Chinese ornament. As a consequence, political interpretations of the material outside of military collections were quickly joined by a strong response to Chinese ornament from cultural institutions and design leaders. Art from the Summer Palace held a prominent place at industrial art exhibitions of the postwar period and inspired new designs in a number of mediums. While the availability of Chinese imperial art was the consequence of a military invasion and therefore a product of imperialist expansion, evidence presented here shows that the design response to looted objects was not circumscribed by this political reality. Chinese ornament on imperial wares was ultimately celebrated for its formal qualities and acknowledged links to the Summer Palace were an indicator of good design, not a celebration of victory over a failed Chinese state. Therefore, the looting of the Summer Palace was ultimately an essential factor in the development of modern design, the essence of which is a break with Classical ornament

    Optical Synchronization of Time-of-Flight Cameras

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    Time-of-Flight (ToF)-Kameras erzeugen Tiefenbilder (3D-Bilder), indem sie Infrarotlicht aussenden und die Zeit messen, bis die Reflexion des Lichtes wieder empfangen wird. Durch den Einsatz mehrerer ToF-Kameras können ihre vergleichsweise geringere Auflösungen überwunden, das Sichtfeld vergrößert und Verdeckungen reduziert werden. Der gleichzeitige Betrieb birgt jedoch die Möglichkeit von Störungen, die zu fehlerhaften Tiefenmessungen führen. Das Problem der gegenseitigen Störungen tritt nicht nur bei Mehrkamerasystemen auf, sondern auch wenn mehrere unabhängige ToF-Kameras eingesetzt werden. In dieser Arbeit wird eine neue optische Synchronisation vorgestellt, die keine zusätzliche Hardware oder Infrastruktur erfordert, um ein Zeitmultiplexverfahren (engl. Time-Division Multiple Access, TDMA) für die Anwendung mit ToF-Kameras zu nutzen, um so die Störungen zu vermeiden. Dies ermöglicht es einer Kamera, den Aufnahmeprozess anderer ToF-Kameras zu erkennen und ihre Aufnahmezeiten schnell zu synchronisieren, um störungsfrei zu arbeiten. Anstatt Kabel zur Synchronisation zu benötigen, wird nur die vorhandene Hardware genutzt, um eine optische Synchronisation zu erreichen. Dazu wird die Firmware der Kamera um das Synchronisationsverfahren erweitert. Die optische Synchronisation wurde konzipiert, implementiert und in einem Versuchsaufbau mit drei ToF-Kameras verifiziert. Die Messungen zeigen die Wirksamkeit der vorgeschlagenen optischen Synchronisation. Während der Experimente wurde die Bildrate durch das zusätzliche Synchronisationsverfahren lediglich um etwa 1 Prozent reduziert.Time-of-Flight (ToF) cameras produce depth images (three-dimensional images) by measuring the time between the emission of infrared light and the reception of its reflection. A setup of multiple ToF cameras may be used to overcome their comparatively low resolution, increase the field of view, and reduce occlusion. However, the simultaneous operation of multiple ToF cameras introduces the possibility of interference resulting in erroneous depth measurements. The problem of interference is not only related to a collaborative multicamera setup but also to multiple ToF cameras operating independently. In this work, a new optical synchronization for ToF cameras is presented, requiring no additional hardware or infrastructure to utilize a time-division multiple access (TDMA) scheme to mitigate interference. It effectively enables a camera to sense the acquisition process of other ToF cameras and rapidly synchronizes its acquisition times to operate without interference. Instead of requiring cables to synchronize, only the existing hardware is utilized to enable an optical synchronization. To achieve this, the camera’s firmware is extended with the synchronization procedure. The optical synchronization has been conceptualized, implemented, and verified with an experimental setup deploying three ToF cameras. The measurements show the efficacy of the proposed optical synchronization. During the experiments, the frame rate was reduced by only about 1% due to the synchronization procedure

    Comparative analysis of 3D- depth cameras in industrial bin picking solution

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    Machine vision is a crucial component of a successful bin picking solution. During the past few years, there has been large advancements in depth sensing technologies. This has led to them receiving a lot of attention, especially in bin picking applications. With reduced costs and greater accessibility, the use of machine vision has rapidly increased. Automated bin picking poses a technical challenge, which is present in numerous industrial processes. Robots need perception from their surroundings, and machine vision attempt to solve this by providing eyes to the machine. The motivation behind solving this challenge is the increased productivity, enabled by automated bin picking. The main goal of this thesis is to address the challenges of bin picking by comparing the performance of different 3D- depth cameras with illustrative case studies and experimental research. The depth cameras are exposed to different ambient conditions and object properties, where the performance of different 3D- imaging technologies is evaluated and compared between each other. The performance of a commercial bin picking solution is also researched through illustrative case studies to evaluate the accuracy, reliability, and flexibility of the solution. Feasibility study is also conducted, and the capabilities of the bin picking solution is demonstrated in two industrial applications. This research work focuses on three different depth sensing technologies. Comparison is done between structured light, stereo vision, and time-of-flight technologies. The main categories for evaluation are ambient light tolerance, reflective surfaces, and how well the depth cameras can detect simple and complex geometric features. The comparison between the depth cameras is limited to opaque objects, ranging from shiny metal blanks to matte connector components and porous surface textures. The performance of each depth camera is evaluated, and the advantages and disadvantages of each technology are discussed. Results of this thesis showed that while all of the technologies are capable of performing in a bin picking solution, structured light performed the best in the evaluation criteria of this thesis. The results from bin picking solution accuracy evaluation also illustrated some of the many challenges of bin picking, and how the true accuracy of the bin picking solution is not dictated purely by the resolution of the vision sensor. Finally, to conclude this thesis the results and future suggestions are discussed.Konenäkö on keskeinen osa automatisoitua kasasta poimintasovellusta. Syvyyskamerateknologiat ovat kehittyneet paljon kuluneiden vuosien aikana, joka on herättänyt paljon keskustelua niiden käyttömahdollisuuksista. Kustannusten alenemisen, sekä paremman saatavuuden myötä konenäön käyttö, erityisesti kasasta poimintasovelluksissa onkin lisääntynyt nopeasti. Automatisoitu kasasta poiminta kuitenkin omaa teknisiä haasteita, jotka ovat läsnä lukuisissa teollisissa prosesseissa. Motivaatio automatisoidun kasasta poiminnan taustalla on tuotettavuuden kasvu, jonka konenäkö mahdollistaa tarjoamalla dataa robotin ympäristöstä. Tämän diplomityön tavoitteina on vastata kasasta poiminnan haasteisiin vertailemalla erilaisten 3D-syvyyskameroiden suorituskykyä tapaustutkimusten sekä kokeellisen tutkimuksen avulla. Syvyyskameroiden toimintaa arvioidaan erilaisissa ympäristöissä sekä erilaisilla kappaleilla, jonka seurauksena 3D-kuvaustekniikoiden suorituskykyä vertaillaan keskenään. Työn aikana arvioidaan myös kaupallisen kasasta poimintasovelluksen suorituskykyä, jossa tutkitaan tapaustutkimusten avulla sovelluksen tarkkuutta, luotettavuutta sekä joustavuutta. Tämän lisäksi sovelluksen toimintaa pilotoidaan, ja ratkaisun ominaisuuksia demonstroidaan kahdessa teollisessa sovelluksessa. Tämä diplomityö keskittyy kolmeen eri syvyyskameratekniikkaan. Vertailu tehdään strukturoidun valon, stereonäön sekä Time-of-Flight tekniikoiden välillä. Arvioinnin pääkategoriat ovat ympäristön valoisuus, geometristen muotojen havainnointikyky, sekä heijastavat pinnat. Syvyyskameroiden välinen vertailu rajoittuu läpinäkymättömiin kappaleisiin, jotka vaihtelevat kiiltävistä metalliaihioista mattapintaisiin liitinkomponentteihin ja huokoisiin pintarakenteisiin. Tutkimuksen tulokset osoittivat, että vaikka kaikki tekniikat kykenevät automatisoituun kasasta poimintaan, strukturoitu valo suoriutui tutkituista teknologioista parhaiten. Kasasta poimintasovelluksen tarkkuuden arviointi havainnollisti myös sen monia haasteita, sekä kuinka sovelluksen todellinen tarkkuus ei riipu ainoastaan syvyyskameran resoluutiosta. Loppupäätelmien lisäksi työ päätetään ehdotuksilla tutkimuksen jatkamiseksi

    The development and influence of Japanese aesthetics and its manifestation in Japanese animation

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    This paper sorts out the evolution and development of Japanese aesthetics chronologically, summarizes the features of Japanese animation, interprets the charm of Japanese animation by linking the characteristics of Japanese culture that correspond to Japanese animation, and eventually discusses the controversial social impact of Japanese culture on China brought by Japanese animation

    Pathway to Future Symbiotic Creativity

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    This report presents a comprehensive view of our vision on the development path of the human-machine symbiotic art creation. We propose a classification of the creative system with a hierarchy of 5 classes, showing the pathway of creativity evolving from a mimic-human artist (Turing Artists) to a Machine artist in its own right. We begin with an overview of the limitations of the Turing Artists then focus on the top two-level systems, Machine Artists, emphasizing machine-human communication in art creation. In art creation, it is necessary for machines to understand humans' mental states, including desires, appreciation, and emotions, humans also need to understand machines' creative capabilities and limitations. The rapid development of immersive environment and further evolution into the new concept of metaverse enable symbiotic art creation through unprecedented flexibility of bi-directional communication between artists and art manifestation environments. By examining the latest sensor and XR technologies, we illustrate the novel way for art data collection to constitute the base of a new form of human-machine bidirectional communication and understanding in art creation. Based on such communication and understanding mechanisms, we propose a novel framework for building future Machine artists, which comes with the philosophy that a human-compatible AI system should be based on the "human-in-the-loop" principle rather than the traditional "end-to-end" dogma. By proposing a new form of inverse reinforcement learning model, we outline the platform design of machine artists, demonstrate its functions and showcase some examples of technologies we have developed. We also provide a systematic exposition of the ecosystem for AI-based symbiotic art form and community with an economic model built on NFT technology. Ethical issues for the development of machine artists are also discussed
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