Stereoscopic Display Research Articles

Fabrication of microlens arrays on curved substrates for large viewing angle integral imaging 3D display

Curved integral imaging for three-dimensional (3D) displays is well-known for offering an immersive experience and a wider display field of view. Presently, numerous techniques for fabricating curved microlens arrays (curved MLA) have been documented. Nevertheless, the majority of prior research relied on indirect approaches, like utilizing flexible substrates or creating molds. This paper introduces a method for directly fabricating microlens arrays (MLAs) on curved quartz glass. Well-designed arrays of controlled adhesive droplets were created on a hydrophilic-hydrophobic patterned surface. The resulting MLAs, manufactured on a curved substrate with a radius of 10 cm and dimensions of 5 cm × 5 cm, exhibit an 826.5 μm diameter, 56 μm inter-lens spacing, and a 4.5 mm focal length. The effective area of the curved MLA measures 45.8 mm × 45.8 mm. The study encompasses the design of a 2D elemental image and its integration with the curved MLA to achieve a compelling 3D display effect. The lateral viewing range is 2.2 cm. Notably, the field of view angle for the MLA, fabricated on a curved substrate, reached 11.2°, surpassing that of planar MLAs. The imaging system delivers an extensive field of view and attains a realistic 3D stereoscopic display effect. This method, employing various masks, facilitates the rapid fabrication of MLAs on substrates with diverse curvatures and sizes.

Dense monocular depth estimation for stereoscopic vision based on pyramid transformer and multi-scale feature fusion

Stereoscopic display technology plays a significant role in industries, such as film, television and autonomous driving. The accuracy of depth estimation is crucial for achieving high-quality and realistic stereoscopic display effects. In addressing the inherent challenges of applying Transformers to depth estimation, the Stereoscopic Pyramid Transformer-Depth (SPT-Depth) is introduced. This method utilizes stepwise downsampling to acquire both shallow and deep semantic information, which are subsequently fused. The training process is divided into fine and coarse convergence stages, employing distinct training strategies and hyperparameters, resulting in a substantial reduction in both training and validation losses. In the training strategy, a shift and scale-invariant mean square error function is employed to compensate for the lack of translational invariance in the Transformers. Additionally, an edge-smoothing function is applied to reduce noise in the depth map, enhancing the model's robustness. The SPT-Depth achieves a global receptive field while effectively reducing time complexity. In comparison with the baseline method, with the New York University Depth V2 (NYU Depth V2) dataset, there is a 10% reduction in Absolute Relative Error (Abs Rel) and a 36% decrease in Root Mean Square Error (RMSE). When compared with the state-of-the-art methods, there is a 17% reduction in RMSE.

Doing more with less: Realistic stereoscopic three-dimensional anatomical modeling from smartphone photogrammetry.

Traditional teaching methods struggle to convey three-dimensional concepts effectively. While 3D virtual models and virtual reality platforms offer a promising approach to teaching anatomy, their cost and specialized equipment pose limitations, especially in disadvantaged areas. A simpler alternative is to use virtual 3D models displayed on regular screens, but they lack immersion, realism, and stereoscopic vision. To address these challenges, we developed an affordable method utilizing smartphone-based 360° photogrammetry, virtual camera recording, and stereoscopic display (anaglyph or side-by-side technique). In this study, we assessed the feasibility of this method by subjecting it to various specimen types: osteological, soft organ, neuroanatomical, regional dissection, and a dedicated 3D-printed testing phantom. The results demonstrate that the 3D models obtained feature a complete mesh with a high level of detail and a realistic texture. Mesh and texture resolutions were estimated to be approximately 1 and 0.2 mm, respectively. Additionally, stereoscopic animations were both feasible and effective in enhancing depth perception. The simplicity and affordability of this method position it as a technique of choice for creating easily photorealistic anatomical models combined with stereoscopic depth visualization.

Modeling and optimizing through plenoptic function for the dual lenticular lens-based directional autostereoscopic display system.

We propose an autostereoscopic display system that ensures full resolution for multiple users by directional backlight and eye tracking technology. The steerable beam formed by directional backlight can be regarded as the result of sparsely sampling the light field in space. Therefore, we intuitively propose an optimization algorithm based on the characterization for the state of the steerable beams, which is computed in matrix form using the plenoptic function. This optimization algorithm aims to optimize the exit pupil quality and ultimately enhancing the viewing experience of stereoscopic display. Numerical simulations are conducted and the improvement in exit pupil quality achieved by the optimization scheme is verified. Furthermore, a prototype of the stereoscopic display that employs dual-lenticular lens sheets for the directional backlight has been constructed using the optimized optical parameters. It provides 9 independent exit pupils at the optimal viewing distance of 400 mm, with an exit pupil resolution of 1/30. The field of view is ±16.7°, the viewing distance range is 380 mm to 440 mm. At the optimal viewing distance 400 mm, the average crosstalk of the system is 3%, and the dynamic brightness uniformity across the entire viewing plane reaches 85%. The brightness uniformity of the display at each exit pupil is higher than 88%.

AMENet is a monocular depth estimation network designed for automatic stereoscopic display.

Monocular depth estimation has a wide range of applications in the field of autostereoscopic displays, while accuracy and robustness in complex scenes are still a challenge. In this paper, we propose a depth estimation network for autostereoscopic displays, which aims at improving the accuracy of monocular depth estimation by fusing Vision Transformer (ViT) and Convolutional Neural Network (CNN). Our approach feeds the input image as a sequence of visual features into the ViT module and utilizes its global perception capability to extract high-level semantic features of the image. The relationship between the losses is quantified by adding a weight correction module to improve robustness of the model. Experimental evaluation results on several public datasets show that AMENet exhibits higher accuracy and robustness than existing methods in different scenarios and complex conditions. In addition, a detailed experimental analysis was conducted to verify the effectiveness and stability of our method. The accuracy improvement on the KITTI dataset compared to the baseline method is 4.4%. In summary, AMENet is a promising depth estimation method with sufficient high robustness and accuracy for monocular depth estimation tasks.

Human binocular color fusion model based on BP Neural Networks prediction

Stereoscopic display vision is significantly impacted by the color distortion of left and right eye images. When the human eye receives a specific range of dissimilar color information separately, the visual system combines them into a single color through binocular color fusion. In this study, we present experimental findings which compare the accuracy of a common binocular color-fusion model that was trained utilizing both linear fitting and back-propagation neural networks. Patient binocular color contrast test data was collected by eye care professionals working in private eye clinics. The results indicated that the back-propagation neural network produced RMSE errors of 0.9819 and 0.9662 for predicting binocular contrast, which were superior to the linear fitting method with errors of approximately 0.5. The BP neural network algorithm employed demonstrates predictive capabilities and lessens the occurrence of color redundancy. This reduction in redundancy holds the potential to decrease expenses associated with stereo imaging in future applications.

35th Annual Stereoscopic Displays and Applications Conference – Introduction

35th Annual Stereoscopic Displays and Applications Conference – Introduction

3D Visual Discomfort Assessment With a Weakly Supervised Graph Convolution Neural Network Based on Inaccurately Labeled EEG.

Visual discomfort significantly limits the broader application of stereoscopic display technology. Hence, the accurate assessment of stereoscopic visual discomfort is a crucial topic in this field. Electroencephalography (EEG) data, which can reflect changes in brain activity, have received increasing attention in objective assessment research. However, inaccurately labeled data, resulting from the presence of individual differences, restrict the effectiveness of the widely used supervised learning methods in visual discomfort assessment tasks. Simultaneously, visual discomfort assessment methods should pay greater attention to the information provided by the visual cortical areas of the brain. To tackle these challenges, we need to consider two key aspects: maximizing the utilization of inaccurately labeled data for enhanced learning and integrating information from the brain's visual cortex for feature representation purposes. Therefore, we propose the weakly supervised graph convolution neural network for visual discomfort (WSGCN-VD). In the classification part, a center correction loss serves as a weakly supervised loss, employing a progressive selection strategy to identify accurately labeled data while constraining the involvement of inaccurately labeled data that are influenced by individual differences during the model learning process. In the feature extraction part, a feature graph module pays particular attention to the construction of spatial connections among the channels in the visual regions of the brain and combines them with high-dimensional temporal features to obtain visually dependent spatio-temporal representations. Through extensive experiments conducted in various scenarios, we demonstrate the effectiveness of our proposed model. Further analysis reveals that the proposed model mitigates the impact of inaccurately labeled data on the accuracy of assessment.

Perceptual Thresholds for Radial Optic Flow Distortion in Near-Eye Stereoscopic Displays.

We provide the first perceptual quantification of user's sensitivity to radial optic flow artifacts and demonstrate a promising approach for masking this optic flow artifact via blink suppression. Near-eye HMOs allow users to feel immersed in virtual environments by providing visual cues, like motion parallax and stereoscopy, that mimic how we view the physical world. However, these systems exhibit a variety of perceptual artifacts that can limit their usability and the user's sense of presence in VR. One well-known artifact is the vergence-accommodation conflict (VAC). Varifocal displays can mitigate VAC, but bring with them other artifacts such as a change in virtual image size (radial optic flow) when the focal plane changes. We conducted a set of psychophysical studies to measure users' ability to perceive this radial flow artifact before, during, and after self-initiated blinks. Our results showed that visual sensitivity was reduced by a factor of 10 at the start and for ~70 ms after a blink was detected. Pre- and post-blink sensitivity was, on average, ~O.15% image size change during normal viewing and increased to ~1.5- 2.0% during blinks. Our results imply that a rapid (under 70 ms) radial optic flow distortion can go unnoticed during a blink. Furthermore, our results provide empirical data that can be used to inform engineering requirements for both hardware design and software-based graphical correction algorithms for future varifocal near-eye displays. Our project website is available at https://gamma.umd.edu/ROF/.

Analysis of the effectiveness of virtual reality technology integration in landscape design

Abstract In this paper, we first studied the 3D visual immersion technology of virtual reality, explored the stereoscopic display and multi-channel stereoscopic display method of virtual reality, and corrected the nonlinear distortion by grating alignment and deformation correction. After that, the model’s lighting technology is examined, and the model’s lighting coefficient is analyzed and calculated. Then, the advantages of landscape design based on virtual reality technology in terms of subjective evaluation, human perception, and promotion of work efficiency were analyzed by comparing traditional landscape design with virtual reality landscape design. The results show that the Sig value of the environmental adaptability of the two spatial designs is 0.037, which is less than 0.05, and there is a significant difference between the two in terms of subjective ratings. People’s attention was enhanced by 7%-10% in the virtual design scene, and the induced brain frequency was 8%-10% higher than that of the traditional landscape design, indicating that the virtual landscape design was more effective.

Integral Imaging Display System Based on Human Visual Distance Perception Model

In an integral imaging (II) display system, the self-adjustment ability of the human eye can result in blurry observations when viewing 3D targets outside the focal plane within a specific range. This can impact the overall imaging quality of the II system. This research examines the visual characteristics of the human eye and analyzes the path of light from a point source to the eye in the process of capturing and reconstructing the light field. Then, an overall depth of field (DOF) model of II is derived based on the human visual system (HVS). On this basis, an II system based on the human visual distance (HVD) perception model is proposed, and an interactive II display system is constructed. The experimental results confirm the effectiveness of the proposed method. The display system improves the viewing distance range, enhances spatial resolution and provides better stereoscopic display effects. When comparing our method with three other methods, it is clear that our approach produces better results in optical experiments and objective evaluations: the cumulative probability of blur detection (CPBD) value is 38.73%, the structural similarity index (SSIM) value is 86.56%, and the peak signal-to-noise ratio (PSNR) value is 31.12. These values align with subjective evaluations based on the characteristics of the human visual system.

Projection of realistic three-dimensional photogrammetry models using stereoscopic display: A technical note.

The 3D stereoscopic technique consists in providing the illusional perception of depth of a given object using two different images mimicking how the right and left eyes capture the object. Both images are slightly different and when overlapped gives a three-dimensional (3D) experience. Considering the limitations for establishing surgical laboratories and dissections courses in some educational institutions, techniques such as stereoscopy and photogrammetry seem to play an important role in neuroanatomy and neurosurgical education. The aim of this study was to describe how to combine and set up realistic models acquired with photogrammetry scans in 3D stereoscopic projections. Three donors, one dry skull, embalmed brain and head, were scanned using photogrammetry. The software used for displaying the final realistic 3D models (Blender, Amsterdam, the Netherlands) is a free software and allows stereoscopic projection without compromising the interactivity of each model. By default, the model was exported and immediately displayed as a red cyan 3D mode. The 3D projector used in the manuscript required a side-by-side 3D mode which was set up with simple commands on the software. The final stereoscopy projection offered depth perception and a visualization in 360° of each donor; this perception was noted especially when visualizing donors with different cavities and fossae. The combination of 3D techniques is of paramount importance for neuroanatomy education. Stereoscopic projections could provide a valuable tool for neuroanatomy instruction directed at clinical trainees and could be especially useful when access to laboratory-based learning is limited.

The Effects of Various Maxillary Sinus Antrostomy Techniques on Modifying the Ventilation and Air-Conditioning Characteristics of the Maxillary Sinus: A Numerical Study

Background and Objectives: Endoscopic sinus surgery is commonly performed for maxillary sinus (MS) disease, and the surgical extent of the MS medial wall or ostium varies. We examined the effect of MS surgery on nasal airflow and air-conditioning using computational fluid dynamics in five nasal cavity numerical models.Methods: Four types of unilateral virtual MS surgery were conducted on the right MS based on computed tomography images of a 49-year-old man with normal anatomy. The five models were as follows: baseline (normal), middle meatal antrostomy (MMA), MMA with inferior meatal antrostomy (MMA+IMA), mega-antrostomy (MEGA), and endoscopic medial maxillectomy (EMM). Virtual simulator software and a stereoscopic display with haptic device were used for virtual surgery. Meshing software and computer fluid dynamics software were used to generate meshes and analyze airflow.Results: The MMA and MMA+IMA results were similar to the baseline model. However, EMM and MEGA exhibited some physiological changes. The amount of airflow moving into the MS was largest in the EMM model, followed by the MEGA model. The distributions of wall shear stress and surface water-vapor increased near the enlarged MS ostium in EMM and MEGA. Skewed airflow partition and different airflow rates between the operated and unoperated sites of the nose also changed the air-conditioning characteristics. EMM substantially reduced the relative humidity in the nasopharynx, and MEGA showed a smaller reduction.Conclusion: Among four surgery techniques, EMM produced the largest increase in wall shear stress and surface water vapor flux on the posterior surface of the MS and the greatest deterioration in the nasal cavity’s air-conditioning capacity. MEGA reduced the local airflow disturbance inside the MS and prevented excessive degeneration of the cavity’s overall air-conditioning capacity. In conclusion, MEGA and modified EMM approaches have physiological advantages over EMM, while securing a sufficient spatial extent of resection for surgery.

Assessment of visual fatigue caused by stereoscopic disparity based on multimodal measurement

Given the prevalence of visual fatigue induced by stereoscopic display, research on the neural mechanism of visual fatigue was limited. The goal of this study was to investigate the effect of stereoscopic display with different horizontal disparities on visual fatigue based on subjective questionnaire, ophthalmological parameters, eye movement and electrocardiogram (ECG). Subjects felt more headache, uncomfortable and dry eyes after watching 70-minute enhanced 3D display with larger negative disparity than normal 3D display. Meanwhile, visual function tear film break-up time (TBUT) reduced, microsaccade mean pupil diameter (MMPD) increased and heart rate variability (HRV) changed more significantly after watching enhanced 3D display. Overall, these results demonstrated that enhanced 3D display had a better sense of immersion, but it induced more visual fatigue significantly than normal 3D display.

P‐57: Spatial Display System Based on Cylindrical Lens Technology

Compared with traditional two‐dimensional displays, three‐dimensional displays can bring users a more realistic visual experience. In recent years, with the development of naked eye 3D technology, users can completely get rid of the shackles of glasses and experience stereoscopic visual effects more freely. The 3D display technology based on the cylindrical lens is a vital technology branch in the field of stereoscopic display. The lens light splitting and eye tracking technology are used to ensure that the image taken into the human eye at any viewing angle has correct parallax, thus giving people a three‐dimensional feeling. BOE has accumulated numerous technologies in the display field, especially in the fields of high‐resolution display and new display. This paper focuses on the space reality display system independently developed by BOE.

Off-Axis Layered Displays: Hybrid Direct-View/Near-Eye Mixed Reality with Focus Cues.

This work introduces off-axis layered displays, the first approach to stereoscopic direct-view displays with support for focus cues. Off-axis layered displays combine a head-mounted display with a traditional direct-view display for encoding a focal stack and thus, for providing focus cues. To explore the novel display architecture, we present a complete processing pipeline for the real-time computation and post-render warping of off-axis display patterns. In addition, we build two prototypes using a head-mounted display in combination with a stereoscopic direct-view display, and a more widely available monoscopic direct-view display. In addition we show how extending off-axis layered displays with an attenuation layer and with eye-tracking can improve image quality. We thoroughly analyze each component in a technical evaluation and present examples captured through our prototypes.

1: Binocular Fusion and Rivalry of Binocular Tone Mapping in Stereoscopic Displays

Binocular fusion and rivalry are indispensable considerations when simulating the real world. The improvement of these two factors is one of the keys to improving three‐dimensional display technology. Based on three visual perception experiments, physiological binocular fusion and rivalry for improving stereo image quality are investigated. The results show that different dynamic ranges modulated by the binocular tone mapping algorithm for each eye result in better stereo image quality and have no significant effect on stereoscopic perception. The study provides a way to enhance the quality of stereoscopic displays based on the human factor.

Pediatric patient-specific three-dimensional virtual models for surgical decision making in resection of hepatic and retroperitoneal tumors.

Typically, preoperative imaging is viewed in two dimensions (2D) only, but three-dimensional (3D) virtual models may improve viewers' anatomical perspective by permitting them to interact with the imaging through manipulating it in space. Research into the utility of these models in most surgical specialties is growing rapidly. This study investigates the utility of 3D virtual models of complex pediatric abdominal tumors for clinical decision making, particularly the decision to proceed with surgical resection or not. 3D virtual models of tumors and adjacent anatomy were created from CT images of pediatric patients scanned for Wilms tumor, neuroblastoma or hepatoblastoma. Pediatric surgeons individually assessed the resectability of the tumors. First, they assessed resectability using the standard protocol of viewing imaging on conventional screens and then reassessed resectability after being presented with the 3D virtual models. Inter-physician agreement on resectability for each patient was analyzed using Krippendorff's alpha. Inter-physician agreement was used as a surrogate for correct interpretation. Participants were also surveyed afterward on the utility and practicality of the 3D virtual models for clinical decision making. Inter-physician agreement when using CT imaging alone was "fair" (Krippendorff's alpha α = 0.399), while inter-physician agreement when using 3D virtual models increased to "moderate" (Krippendorff's alpha α = 0.532). When surveyed about model utility, all 5 participants considered them helpful. Two participants felt the models would be practical for clinical use in most cases, while 3 felt they would be practical for select cases only. This study demonstrates the subjective utility of 3D virtual models of pediatric abdominal tumors for clinical decision making. The models are an adjunct that can be particularly useful in complicated tumors that efface or displace critical structures that may impact resectability. Statistical analysis demonstrates the improved inter-rater agreement with the 3D stereoscopic display over the 2D display. The use of 3D displays of medical images will increase over time, and evaluation of their potential usefulness in various clinical settings is necessary.

Benefit of stereoscopic volume rendering for the identification of pediatric pulmonary vein stenosis from CT angiography.

The use of three-dimensional (3D) technologies in medical practice is increasing; however, its use is largely untested. One 3D technology, stereoscopic volume-rendered 3D display, can improve depth perception. Pulmonary vein stenosis (PVS) is a rare cardiovascular pathology, often diagnosed by computed tomography (CT), where volume rendering may be useful. Depth cues may be lost when volume rendered CT is displayed on regular screens instead of 3D displays. The objective of this study was to determine whether the 3D stereoscopic display of volume-rendered CT improved perception compared to standard monoscopic display, as measured by PVS diagnosis. CT angiograms (CTAs) from 18 pediatric patients aged 3 weeks to 2 years were volume rendered and displayed with and without stereoscopic display. Patients had 0 to 4 pulmonary vein stenoses. Participants viewed the CTAs in 2 groups with half on monoscopic and half on stereoscopic display and the converse a minimum of 2 weeks later, and their diagnoses were recorded. A total of 24 study participants, comprised of experienced staff cardiologists, cardiovascular surgeons and radiologists, and their trainees viewed the CTAs and assessed the presence and location of PVS. Cases were classified as simple (2 or fewer lesions) or complex (3 or more lesions). Overall, there were fewer type 2 errors in diagnosis for stereoscopic display than standard display, an insignificant difference (p = 0.095). There was a significant decrease in type 2 errors for complex multiple lesion cases (≥3) vs simpler cases (p = 0.027) and improvement in localization of pulmonary veins (p = 0.011). Subjectively, 70% of participants stated that stereoscopy was helpful in the identification of PVS. The stereoscopic display did not result in significantly decreased errors in PVS diagnosis but was helpful for more complex cases.

Comparison of changes in visual fatigue and ocular surface after 3D and 2D viewing with augmented reality glasses

The extensive use of electronic devices commonly results in visual discomfort, particularly in stereoscopic display. Augmented Reality (AR) is a mixed technology that superimposes three-dimensional (3D) digital data onto an image of reality. Even though the visual health evaluation of 3D contents has been widely concerned, the difference between 3D and two-dimensional (2D) viewing using AR display was rarely studied. We aimed to compare the changes in visual fatigue and ocular surface parameters after 3D and 2D viewing with optical waveguide AR glasses for one hour (1hr). In the experiment, thirty young healthy participants watched the same film in 2D and 3D mode separately using AR glasses with one week interval. Subjective visual fatigue questionnaire and ocular examinations were evaluated at 3 time points: pre-watching, post-2D and post-3D visual task for 1hr. Lipid layer thickness (LLT) and total blink (TB) were evaluated with the LipiView interferometer. Tear meniscus height (TMH) and noninvasive tear breakup time (NIBUT) were measured using Keratograph 5M. The effect of viewing 2D and 3D videos for 1hr with AR glasses suggested slight visual discomfort except the symptom of pain and dullness. The lipid layer thickness and total blink showed increasing trends in both post-visual task but more obvious after 2D viewing. Blinking patterns and tear film stability are meaningful for video display terminal users in visual health education. Ocular parameters are needed to be considered in the design and usage of future AR applications.