À l'heure actuelle, la voiture n'est plus un objet qui permet seulement de transporter une personne d'un endroit à un autre et il suffit de regarder les publicités automobiles pour en avoir la certitude. En effet, le champ lexical utilisé dans ces dernières se rapproche plus des sens, voire du rêve, que de la mobilité. La voiture n'est donc plus reléguée au simple rang de transporteur, mais à celui de véritable habitat dans lequel nous sommes amenés à découvrir de nouvelles sensations. Dans ce cadre, la réalité virtuelle est l'un des outils qui est utilisé dans l'industrie automobile afin de vérifier, en amont, l'ergonomie d'un prototype. En effet, en immergeant partiellement un usager dans cette autre réalité, il est possible d'avoir des retours pertinents quant à une maquette numérique, une interface, etc. Cela permet ainsi de tester différentes pièces avant même leur production ce qui est un gain notable en temps et en argent. Cependant, l'utilisation de cette technologie pose des questions quant au photo-réalisme de la reproduction virtuelle, et ce, tout particulièrement lorsque des pièces tels que les blocs optiques de la voiture sont analysés. Sur cette thématique, des études antérieures ont montré que le système reproduisait correctement les intensités lumineuses, mais pas la couleur des phares. Ainsi, dans le contexte du rendu de phare photoréaliste, nous avons tout d'abord proposé deux échelles colorimétriques afin d'analyser à quel point nous pouvions nous éloigner de la réalité sans que la différence de couleur ne gêne l'utilisateur final. À la suite de cela, nous avons proposé un système qui suit, au jour le jour, le vieillissement du simulateur dans le but de corriger ladite différence colorimétrique. Enfin, dans une étude exploratoire, nous avons souhaité regarder comment le comportement des conducteurs pouvait être influencé par la couleur des phares de voiture. Nous supposions que ce facteur pouvait avoir un impact sur la perception des distances et donc sur la distance intervéhiculaire à laquelle le conducteur se positionnait. / Nowadays, a car is not limited to the transportation of one or many people. Indeed, if we take a look at some automobile advertisement, it's more the idea of desir or even dream that is conveyed. Therefore, a car is no longer related to the simple rank of carrier but is a real new habitat in which we will discover new sensations. In this context, the car company that offers the best experience at the better price should be the one that dominates the market. For that purpose, virtual reality is one of the tools that is used by the automotive industry. Indeed, by partially immerging a user in this "other" reality, it is possible to get a relevent feedback for a digital model, Human-Machine Interface, etc. This allows to test different pieces before their production which is a significant gain in time and money. However, the use of this technology raises questions about the fidelity of the reproduction. Do the virtual reproduction of an object is close enough to the original ? If there is a difference, how could it impact the judgment of a person ? Those questions are even more important when it comes to the virtual evaluation of car headlight because they must respect international standard in term of color and light intensity. For these points, previous studies have shown that the system correctly reproduced the light intensities but not the headlights color. Thus, in the context of rendering photorealistic headlights, we first investigate on how a color difference can affect, discomfort the headlight specialist. To this end, we lead psychometric experiments and proposed two color difference scales (one for a naïve population and the other for an expert one). With this first result, we have proposed a system that follows, day by day, the aging simulator in order to correct the said color difference. Finally, in an exploratory study, we wanted to look at how the driver behavior could be influenced by the color of the car headlights. We assumed that this factor could affect depth perception and therefore the distance intercar in which the driver was positioning.

Virtual reality (VR) for surgical training shows promise in preparing surgeons for complex procedures. However, achieving a high level of realism in VR is essential for the skills acquired to translate effectively into real-world applications. One challenge is the underestimation of perceived depth in VR compared to the real world, which can significantly impact applications requiring precise depth perception. This study aims to investigate how object shape influences depth perception in VR, as it may contribute to the observed underestimation of distances. Specifically, the research focuses on minimally invasive neurosurgery (MIS), where surgeons operate through small incisions on the skull without direct visualization of the inside of the skull. Training in a highly accurate VR simulation could offer a safe practice environment for surgeons. Previous studies have explored the use of VR for training in various fields, including medicine, transport, and military applications. However, concerns exist regarding whether VR accurately represents real-life scenarios, particularly with regard to depth perception. Research indicates that participants often underestimate egocentric distances in VR, which can pose challenges in MIS procedures where precise targeting is crucial. This study builds upon previous research conducted by KTH master’s students in 2022, which examined spatio-temporal distance perception in VR. This study expands on this work by investigating the influence of object shape on depth perception. Previous research has shown that different object shapes, luminance, and colors can impact depth perception in VR. Understanding how object shape affects depth perception can contribute to improving the realism of VR simulations for surgical training, particularly for MIS procedures. / Virtual Reality (VR) i utbildningssyfte inom kirurgi visar lovande resultat för att utbilda kirurger inför komplexa ingrepp. Dock är det viktigt att uppnå en hög grad av realism i VR för att de förvärvade färdigheterna ska kunna överföras till verkliga tillämpningar. En utmaning är att tidigare studier visat på att VR har en negativ inverkan på djupseendet, vilket kan ha en betydande påverkan på tillämpningar som kräver exakt djupseende. Denna studie syftar till att undersöka hur ett objekts form påverkar djupseendet i VR. Specifikt fokuserar vår studie på minimalinvasiv hjärnkirurgi (MIS), där kirurger utför ingrepp genom små snitt som görs i skallen med begränsad insyn. Träning i en VR-simulering kan erbjuda en säker övningsmiljö för kirurger. Tidigare studier har utforskat användningen av VR för träning inom olika områden, inklusive medicin, transport och militära tillämpningar. Dock finns det en oro för huruvida VR korrekt återger verkliga scenarion, särskilt med avseende på djupseendet. Forskning indikerar att deltagare ofta underskattar egocentriska avstånd i VR, vilket kan utgöra en utmaning för MIS-ingrepp där små avstånd är avgörande. Denna studie bygger på tidigare forskning utförd av masterstudenter vid KTH 2022, vilken undersökte uppfattningen av rumtid i VR. Denna studie bygger vidare på denna forskning genom att undersöka hur objektets form påverkar djupseendet. Tidigare forskning har visat att olika objektformer, ljusstyrkor och färger kan påverka djupseendet i VR. Att förstå hur objektets form påverkar djupseendet kan bidra till att förbättra realismen i VR-simuleringar för kirurgisk träning, särskilt för MIS-ingrepp.

Augmented reality (AR) is a very promising display technology with many compelling industrial applications. However, before it can be used in actual settings, its fidelity needs to be investigated from a user-centric viewpoint. More specifically, how distance to the virtual objects is perceived in augmented reality is still an open question. To the best of our knowledge, there are only four previous studies that specifically studied distance perception in AR within reaching distances. Therefore, distance perception in augmented reality still remains a largely understudied phenomenon. This document presents research in depth perception in augmented reality in the near visual field. The specific goal of this research is to empirically study various measurement techniques for depth perception, and to study various factors that affect depth perception in augmented reality, specifically, eye accommodation, brightness, and participant age. This document discusses five experiments that have already been conducted. Experiment I aimed to determine if there are inherent difference between the perception of virtual and real objects by comparing depth judgments using two complementary distance judgment protocols: perceptual matching and blind reaching. This experiment found that real objects are perceived more accurately than virtual objects and matching is a relatively more accurate distance measure than reaching. Experiment II compared the two distance judgment protocols in the real world and augmented reality environments, with improved proprioceptive and visual feedback. This experiment found that reaching responses in the AR environment became more accurate with improved feedback. Experiment III studied the effect of different levels of accommodative demand (collimated, consistent, and midpoint) on distance judgments. This experiment found nearly accurate distance responses in the consistent and midpoint conditions, and a linear increase in error in the collimated condition. Experiment IV studied the effect of brightness of the target object on depth judgments. This experiment found that distance responses were shifted towards background for the dim AR target. Lastly, Experiment V studied the effect of participant age on depth judgments and found that older participants judged distance more accurately than younger participants. Taken together, these five experiments will help us understand how depth perception operates in augmented reality.

Accurate and usable x-ray vision has long been a goal in augmented reality (AR) research and development. X-ray vision, or the ability to comprehend location and object information when such is viewed through an opaque barrier, would be imminently useful in a variety of contexts, including industrial, disaster reconnaissance, and tactical applications. In order for x-ray vision to be a useful tool for many of these applications, it would need to extend operators’ perceptual awareness of the task or environment. The effectiveness with which x-ray vision can do this is of significant research interest and is a determinant of its usefulness in an application context. In substance, then, it is crucial to evaluate the effectiveness of x-ray vision—how does information presented through x-ray vision compare to real-world information? This approach requires narrowing as x-ray vision suffers from inherent limitations, analogous to viewing an object through a window. In both cases, information is presented beyond the local context, exists past an apparently solid object, and is limited by certain conditions. Further, in both cases, the naturally suggestive use cases occur over action space distances. These distances range from 1.5 to 30 meters and represent the area in which observers might contemplate immediate visually directed actions. These actions, simple tasks with a visual antecedent, represent action potentials for x-ray vision; in effect, x-ray vision extends an operators’ awareness and ability to visualize these actions into a new context. Thus, this work seeks to answer the question “Can a real window be replaced with an AR window?” This evaluation focuses on perceived object location, investigated through a series of experiments using visually directed actions as experimental measures. This approach leverages established methodology to investigate this topic by experimentally analyzing each of several distinct variables on a continuum between real-world depth perception and fully realized x-ray vision. It was found that a real window could not be replaced with an AR window without some loss of depth perception acuity and accuracy. However, no significant difference was found between a target viewed through an opaque wall and a target viewed through a real window.

Interacting with a Virtual Environment (VE) generally requires the user to correctly perceive the relative position and orientation of virtual objects. For applications requiring interaction in personal space, the user may also need to accurately judge the position of the virtual object relative to that of a real object, for example, a virtual button and the user's real hand. This is difficult since VEs generally only provide a subset of the cues experienced in the real world. Complicating matters further, VEs presented by currently available visual displays may be inaccurate or distorted due to technological limitations. Fundamental physiological and psychological aspects of vision as they pertain to the task of object manipulation were thoroughly reviewed. Other sensory modalities--proprioception, haptics, and audition--and their cross-interactions with each other and with vision are briefly discussed. Visual display technologies, the primary component of any VE, were canvassed and compared. Current applications and research were gathered and categorized by different VE types and object interaction techniques. While object interaction research abounds in the literature, pockets of research gaps remain. Direct, dexterous, manual interaction with virtual objects in Mixed Reality (MR), where the real, seen hand accurately and effectively interacts with virtual objects, has not yet been fully quantified. An experimental test bed was designed to provide the highest accuracy attainable for salient visual cues in personal space. Optical alignment and user calibration were carefully performed. The test bed accommodated the full continuum of VE types and sensory modalities for comprehensive comparison studies. Experimental designs included two sets, each measuring depth perception and object interaction. The first set addressed the extreme end points of the Reality-Virtuality (R-V) continuum--Immersive Virtual Environment (IVE) and Reality Environment (RE). This validated, linked, and extended several previous research findings, using one common test bed and participant pool. The results provided a proven method and solid reference points for further research. The second set of experiments leveraged the first to explore the full R-V spectrum and included additional, relevant sensory modalities. It consisted of two full-factorial experiments providing for rich data and key insights into the effect of each type of environment and each modality on accuracy and timeliness of virtual object interaction. The empirical results clearly showed that mean depth perception error in personal space was less than four millimeters whether the stimuli presented were real, virtual, or mixed. Likewise, mean error for the simple task of pushing a button was less than four millimeters whether the button was real or virtual. Mean task completion time was less than one second. Key to the high accuracy and quick task performance time observed was the correct presentation of the visual cues, including occlusion, stereoscopy, accommodation, and convergence. With performance results already near optimal level with accurate visual cues presented, adding proprioception, audio, and haptic cues did not significantly improve performance. Recommendations for future research include enhancement of the visual display and further experiments with more complex tasks and additional control variables.

Finding if color has an effect on depth perception in virtual reality (VR) is important, as it could be important for e.g. surgeons to perceive the depth correctly if they were to be trained in VR environments as a preparation for surgeries on real patients. If color has an effect on perceived depth in VR then producers of these simulations have to take their color choices into account when creating simulations. Previous research has shown that luminosity and hue can have effects on depth perception. It is also perceived that depth underestimation is prevalent in VR. Discerning if either the color of the focal object or the background is affecting the depth perception is important. Therefore finding what effect different color attributes of a focal object and background has on the depth perception in a VR environment is important. This experimental study examined this through a case study performed in a VR environment built in Unity. The tests were set up to emulate the piercing of a catheter into a plane, where the user pressed a button the moment the plane was pierced. To test different colors of the focal object, in this case a plane, the background was assigned neutral colors (white or black) and while testing the background the plane had a neutral color (white). Results from the study show that colors have a small effect, namely up to 13.2 mm error (for the yellow hue with high luminosity and high saturation), on users’ depth perception in VR. No single attribute was better than another but on the object, blue hue gave the largest error while red hue gave the smallest error. For the background, there was more variation on the data but green and blue hue gave the smallest errors and red and yellow the largest. In sum, color has differing effects on depth perception in VR depending on if the color is applied to a background or an object. Red color gave the most accurate depth perception when applied to the object. For color applied to the background, green hue with high luminosity and blue hue with low luminosity resulted in the most accurate depth perception. / Att ta reda på om färg har en påverkan på djupseende i virtuell verklighet (VR) är viktigt, eftersom det skulle vara viktigt för t.ex. kirurger att uppfatta djupet korrekt om de skulle bli tränade i VR miljöer som en förberedelse inför operationer på riktiga patienter. Om färg har en effekt på upplevd djup i VR, då måste tillverkarna av dessa simulationer ha deras färgval i åtanke när de skapar simulatorerna. Tidigare forskning har visat att ljusintensitet och kulörton kan ha en effekt på djupseende. Det har också upptäckts att djupunderskattning är allmänt förekommande i VR. Att urskilja om antingen färgen på fokusobjektet eller på bakgrunden påverkar djupseendet är viktigt. Således att hitta vilken effekt olika färg attribut av ett fokusobjekt och bakgrund har på djupseendet i en VR miljö. Studien undersökte detta genom en fallstudie i en VR miljö byggd i Unity. Testen var uppbyggda för att efterlikna en kateter som genomtränger ett plan där användaren trycker på en knapp då den trängde igenom planet. För att testa olika färger på fokusobjektet, i detta fall ett plan, blev bakgrunden tilldelad neutrala färger (vit och svart) och när bakgrunden testades var planet tilldelad en neutral färg (vit). Resultaten från studien visar att färg har en liten effekt, upp till 13.2 mm i fel (för den gula kulörtonen med hög ljusintensitet och hög mättnad), på djupseende i VR. Inget enskilt attribut var bättre än ett annat, men på objektet gav blå kulörton det största felet medan röd kulörton gav det minsta felet. För bakgrunden var det mer variation på data men grön och blå kulörton gav de minsta felen och röd och gul gav de största felen. Färgen har olika påverkan på djupseende i VR beroende på om färgen är applicerad på en bakgrund eller ett objekt. Röd färg gav det mest korrekta djupseendet när den var applicerad på objektet. För färg applicerad på bakgrund, resulterade grön kulörton med hög ljusintensitet och blå kulörton med låg ljusintensitet i det mest korrekta djupseendet.

One of the main goals of augmented reality is placing virtual content in the real world at a precise location. To achieve this goal, the Head Mounted Display (HMD) should be able to place virtual content at a precise location, and the users should be able to perceive at the exact location. However, achieving this task is very challenging. Since the birth of augmented reality, researchers have been trying to design AR glasses which can do this. Recently AR researchers by taking advantage of SLAM algorithms are able to come closer to the first phase of this goal. Microsoft designed and manufactured a pair of smart glasses called the HoloLens. It is well known for its advanced SLAM algorithm to place the content in a precise location as close as possible. However, there is no significant research on the perceptual location of the virtual content which are placed through Hololens. Therefore this thesis presents a method for measuring the perceived location of virutal objects, and presents an experiment, where these measurements are made with the Hololens. Through this experiment, interesting information about HoloLens was found, such as the capability of regaining tracking immediately after occlusion, rightward error about the horizontal plane, and bias of floating the virtual content above the surface, and objects that appear to close to the observer. Therfore Hololens is an advanced AR display, it still suffers from these problems.

In this thesis, three kinds of depth perception symbols are designed and evaluated with an implemented Augmented Reality prototype. The three types of depth perception symbol's purpose are to intuitively visualize depth for objects whose position is too far away to see without technical assistance. The area needed to be aware of is increasing with time since weapons are developed to operate at farther distances. The symbols, together with Augmented Reality, could improve the situational awareness of dismounted soldiers during navigation and in that way allow the soldiers to be aware of a larger area.  This thesis aims to investigate if the natural depth perception cues Relative size, Aerial effect, and Drop-line effect improve the depth perception of virtual symbols displayed on a handheld 2D screen with Augmented Reality.  The three different depth perception cues were integrated into the three symbol designs. The symbol designs were then put into an Augmented Reality prototype that was used during an explorative user study with eight participants. Both qualitative and quantitative data were collected with a presurvey, interviews, and a post-test-questionnaire.  The study's results indicate that the three depth perception cues intuitively visualize depth when integrated into the three symbol designs. The most intuitive symbol design combined the three depth perception cues. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

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The increased reliance on night operations by the military over the last few decades has led to the development of various night imaging devices. Night vision goggles (NVGs) are one device which have gained widespread use in nighttime helicopter operations. However, rotorcraft accident data have indicated an increased occurrence of "pilot error" type accidents when NVGs are in use. NVG related accidents often can be linked to extremely poor ambient lighting and contrast conditions during nighttime operations as well as the imaging limitations of the NVGs. Research has shown that NVGs reduce visual acuity and depth perception when compared to unaided daylight viewing conditions. In this study the effects of illumination and contrast on stereoscopic vision with and without AN/AVS-6 goggles were investigated. Stereoacuity was measured using a modified Howard-Dolman apparatus with four levels of illumination and three levels of contrast. Testing was performed with NVGs for nighttime illuminations and unaided for daytime levels of illumination. Image measurements were performed on the NVGs to determine the impact of illumination on resolution and signal-to-noise ratio. Stereoscopic vision with NVGs was found to be significantly worse than under daylight conditions. Low levels of contrast also were found to reduce stereoacuity significantly. It was found that the worst stereoacuity in this study occurred under half moon or higher illumination levels. This research revealed that further NVG development should focus on the limitations of the NVGs under high light levels, and special considerations should be made for using NVGs in low contrast, high luminance situations. / Master of Science