Depth Plane Research Articles

Effect of attention on ensemble perception: Comparison between exogenous attention, endogenous attention, and depth.

Ensemble perception is an important ability of human beings that allows one to extract summary information for scenes and environments that contain information that far exceeds the processing limit of the visual system. Although attention has been shown to bias ensemble perception, two important questions remain unclear: (1) whether direct manipulations on different types of spatial attention could produce similar effects on ensembles and (2) whether factors potentially influencing the attention distribution, such as depth perception, could evoke an indirect effect of attention on ensemble representation. This study aims to address these questions. In Experiments 1 and 2, two types of precues were used to evoke exogenous and endogenous attention, respectively, and the ensemble color perceptions were examined. We found that both exogenous and endogenous attention biased ensemble representation towards the attended items, and the latter produced a greater effect. In Experiments 3 and 4, we examined whether depth perception could affect color ensembles by indirectly influencing attention allocation in 3D space. The items were separated in two depth planes, and no explicit cues were applied. The results showed that color ensemble was biased to closer items when depth information was task relevant. This suggests that ensemble perception is naturally biased in 3D space, probably through the mechanism of attention. Computational modeling consistently showed that attention exerted a direct shift on the ensemble statistics rather than averaging the feature values over the cued and noncued items, providing evidence against an averaging process of individual perception.

The effect of retinal sizes on ensemble size judgments of objects in different depth planes

The effect of retinal sizes on ensemble size judgments of objects in different depth planes

Depth-of-field enhancement in light field display based on fusion of voxel information on the depth plane

To improve the performance of 3D light field display(LFD) devices and optimize their display effects, a depth-of-field (DOF) enhancement in LFD based on fusion of voxel information on the depth plane is proposed. In previous research, a calculation method was developed to calculate the voxel size on the depth plane. According to this calculation method, a distribution model of voxel varying with display depth is established. A DOF determination criterion based on voxel distribution from visual perspective is proposed, and its accuracy is validated through subjective experiments involving multiple participants. By fusing the voxels on the depth plane, the phenomenon of voxel overlap is improved, resulting in enhanced definition of 3D images on the depth plane. Under the condition that the structure and parameters of the 3D LFD device are determined, the maximum achievable display depth will be increased significantly. Finally, experimental validation of the method's feasibility is conducted using multiple 3D light field devices for display.

Point Spread Function And Spatial Resolution Analysis Of Multi-Focus Plenoptic Cameras

With the recent development of plenoptic cameras, light field imaging has become a reliable solution for 3D metrology. Plenoptic cameras allow recovering the 3D information of a scene with a single acquisition and only one camera. These advantages make light field imaging particularly interesting for the metrology of two-phase flows. The measurement depth of a back-light imaging setup can be determined by the calibration of the Point Spread function (PSF) of the optical system. This study provides a method adapted to multi-focus plenoptic cameras to measure the PSF width from reconstructed images. We used a calibration target composed of multiple calibrated opaque disks and a diffuse backlight illumination set-up. The PSF width is estimated by measuring the grayscale gradient at the interface of the images of the disks. Coupled with the depth information provided by the plenoptic camera, we obtained the evolution of the PSF at different depth planes. The information on the PSF enables us to obtain the focus criterion, which sets the limits of the measurement volume. The spatial resolution of the reconstructed images is obtained from the PSF. The results obtained for the resolution as a function of virtual depth are consistent with results from previous studies.

Bilateral, symmetrical, tripartite variation of the anterior belly of digastric muscle

BackgroundThe anterior and posterior bellies of digastric muscle act to facilitate components of phonation, jaw opening, and hyoid bone stabilization during swallowing. Variations in the digastric muscle within the submental triangle are well-documented in the literature. Ongoing and up-to-date reporting and knowledge of these variations is important from a clinical perspective. MethodRoutine human anatomical dissection of the anterior neck in a male donor revealed bilateral pairs of accessory muscles (n = 4) attached to and within the depth plane of right and left anterior bellies of digastric muscles. ResultsThe case presented here is of a bilateral, tripartite digastric muscle variation within the submental triangle of an anatomical donor. Attachments and relationships were noted. Variant digastric muscles were found to be innervated by the nerve to the mylohyoid muscle and supplied by the submental artery, consistent with supply to the anterior belly of the digastric muscle. ConclusionThe clinical relevance of these additional muscles primarily pertains to radiological evaluation and reconstructive surgical procedures in the submental region, as digastric muscle bellies serve as essential landmarks and potential targets. Describing anatomical variations is crucial for appropriate planning of interventions in this region.

Multi-depth imaging head-up display using broadband composite holographic optical elements

In order to address the problem of limited imaging planes in the depth direction of traditional automotive head up displays (HUDs), we proposed a kind of HUD with multi-depth imaging capability using broadband composite holographic elements, which can simultaneously project driving information in far, middle, and near depth planes. The system integrates a micro LED digital projector, a composite dispersion compensation element (CDCE) and a composite holographic combiner (CHC) into a compact structure. The images output from a single micro LED projector are projected to different depth planes by the CDCE and CHC. Dispersion blurring of holographic optical elements (HOEs) using broadband incoherent LED illumination is solved by the dispersion compensation characteristics between the holographic elements. This HUD system is capable of projecting high-resolution images on depth planes of z = 2.3 m, z = 0.55 m, and z = 0.3 m, respectively, with the resolutions of 11.57 lp/mm, 13.2 lp/mm, and 15.4 lp/mm with a 6.5° horizontal field of view. Using LED as light source, the system not only avoids speckle noise and safety hazards from laser, but also reduces illumination costs and expands the applicability of HOEs. Meanwhile, the HUD system has high transparency and effective virtual and real information integration ability, which has promising application prospects.

Speckle reduction for single sideband-encoded computer-generated holograms by using an optimized carrier wave

Computer-generated hologram (CGH) is an evolving field that facilitates three-dimensional displays, with speckle noise reduction being a pivotal challenge. In hologram synthesis, complex data with random phase distributions are typically employed as carrier waves for wide viewing angles and a shallow depth of focus (DOF). However, these carrier waves are a source of speckle noise, which can significantly degrade image quality. In this paper, we propose a novel technique for speckle reduction for single sideband (SSB)-encoded holograms, applicable to any arbitrary 3D object. The proposed method focuses on optimizing the random carrier wave used in the hologram synthesis to achieve a uniform amplitude distribution at the object's location. This optimization results in a carrier wave that consistently exhibits uniform amplitude at specific depth planes, leading to a significant reduction of the speckle occurring from the carrier wave. The proposed method has been validated through simulations and optical experiments.

The influence of depth on object selection and manipulation in visual working memory within a 3D context.

Recent studies have examined whether the internal selection mechanism functions similarly for perception and visual working memory (VWM). However, the process of how we access and manipulate object representations distributed in a 3D space remains unclear. In this study, we utilized a memory search task to investigate the effect of depth on object selection and manipulation within VWM. The memory display consisted of colored items half positioned at the near depth plane and the other half at the far plane. During memory maintenance, the participants were instructed to search for a target representation and update its color. The results showed that under object-based attention (Experiments 1, 3, and 5), the update time was faster for targets at the near plane than for those at the far plane. This effect was absent in VWM when deploying spatial attention (Experiment 2) and in visual search regardless of the type of attention deployed (Experiment 4). The differential effects of depth on spatial and object-based attention in VWM suggest that spatial attention primarily relied on 2D location information irrespective of depth, whereas object-based attention seemed to prioritize memory representations at the front plane before shifting to the back. Our findings shed light on the interaction between depth perception and the selection mechanisms within VWM in a 3D context, emphasizing the importance of ordinal, rather than metric, spatial information in guiding object-based attention in VWM.

Modulational Instability of Nonlinear Wave Packets within (2+4) Korteweg–de Vries Equation

The higher-order nonlinear Schrödinger equation with combined nonlinearities is derived by an asymptotic reduction from the (2+4) Korteweg–de Vries model for weakly nonlinear wave packets for the context of interfacial waves in a three-layer symmetric media. Focusing properties and modulation instability effects are discussed for the considered physical context. Instability growth rate, maximum of the increment and the boundaries of the instability interval are derived in terms of three-layer density stratification, their structure on the parameter planes of relative layer depth, carrier wavenumber and envelope amplitude, are considered in detail.

Mono‐MVS: textureless‐aware multi‐view stereo assisted by monocular prediction

AbstractThe learning‐based multi‐view stereo (MVS) methods have made remarkable progress in recent years. However, these methods exhibit limited robustness when faced with occlusion, weak or repetitive texture regions in the image. These factors often lead to holes in the final point cloud model due to excessive pixel‐matching errors. To address these challenges, we propose a novel MVS network assisted by monocular prediction for 3D reconstruction. Our approach combines the strengths of both monocular and multi‐view branches, leveraging the internal semantic information extracted from a single image through monocular prediction, along with the strict geometric relationships between multiple images. Moreover, we adopt a coarse‐to‐fine strategy to gradually reduce the number of assumed depth planes and minimise the interval between them as the resolution of the input images increases during the network iteration. This strategy can achieve a balance between the computational resource consumption and the effectiveness of the model. Experiments on the DTU, Tanks and Temples, and BlendedMVS datasets demonstrate that our method achieves outstanding results, particularly in textureless regions.

Orbital Development in Children with Retinoblastoma: An Imaging-Based Study

ABSTRACT Purpose To examine whether children treated for Retinoblastoma (Rb) have impaired orbital development. Methods A retrospective case series was performed among children with Rb treated at a single medical center from 2004 to 2020. Orbital volumes and measurements were assessed by 3-dimensional image processing software. The main outcome measures were differences in orbital growth between Rb and non-Rb eyes assessed at last follow-up. Results Among 44 patients included (mean age 16.09 ± 18.01 months), a positive correlation between age and orbital volume was observed only in the uninvolved, healthy eyes (p = .03). In unilateral cases, orbital growth in the horizontal, vertical, and depth planes was smaller on the affected side compared to the healthy eyes (p < .05). Orbits that underwent enucleation showed decreased growth over time compared to those treated conservatively (p = .017). Conclusions Orbital growth rate is slower in the orbits of children treated for Rb compared to healthy orbits. Enucleation negatively affects orbital growth.

Source Depth Discrimination Using Intensity Striations in the Frequency–Depth Plane in Shallow Water with a Thermocline

A source depth discrimination method based on intensity striations in the frequency–depth plane with a vertical linear array in a shallow water environment is proposed and studied theoretically and experimentally. To quantify the orientation of the interference patterns, a generalized waveguide variant (GWV) η is introduced. Due to the different dominance of the mode groups, the GWV distribution in the surface source is sharply peaked, indicating the presence of striations in the interferogram and the slope associated with the source–array range, while the distribution of the submerged source is more diffuse, and its interferogram is chaotic. The existence or lack of a distinct peak is used to separate the surface and submerged source classes. The method does not demand prior knowledge of the sound speed profile or the relative movement between the source and the array. In addition, it is the presence of the striations, not the value of η, that is exploited to separate the surface and submerged source classes, which means the source–array range can be unknown. The proposed method is validated using experimental data on the towing ship in SWellEx–96 and numerical modeling. The method’s performance under noise situations and for different source–array ranges is also investigated.

Enhancing the spatial resolution of light-field displays without losing angular resolution by a computational subpixel realignment.

Low spatial resolution is an urgent problem in integral imaging light-field displays (LFDs). This study proposes a computational method to enhance the spatial resolution without losing angular resolution. How rays reconstruct voxels through lenslets is changed so that every ray through a lenslet merely provides a subpixel. The three subpixels of a pixel no longer form one voxel but three independent voxels. We further demonstrate imperfect integration of subpixels, called the sampling error, can be eliminated on specific image depths, including the central depth plane. By realigning subpixels in the above manner under no sampling error, the sampling rate of voxels is three times the conventional pixel-based LFDs. Moreover, the ray number of every voxel is preserved for an unaffected angular resolution. With unavoidable component alignment errors, resolution gains of 2.52 and 2.0 are verified in simulation and experiment by computationally updating the elemental image array. The proposed computational method further reveals that LFDs intrinsically have a higher space-bandwidth product than presumed.

The effect of different depth planes during a manual tracking task in three-dimensional virtual reality space

Unlike ballistic arm movements such as reaching, the contribution of depth information to the performance of manual tracking movements is unclear. Thus, to understand how the brain handles information, we investigated how a required movement along the depth axis would affect behavioral tracking performance, postulating that it would be affected by the amount of depth movement. We designed a visually guided planar tracking task that requires movement on three planes with different depths: a fronto-parallel plane called ROT (0), a sagittal plane called ROT (90), and a plane rotated by 45° with respect to the sagittal plane called ROT (45). Fifteen participants performed a circular manual tracking task under binocular and monocular visions in a three-dimensional (3D) virtual reality space. As a result, under binocular vision, ROT (90), which required the largest depth movement among the tasks, showed the greatest error in 3D. Similarly, the errors (deviation from the target path) on the depth axis revealed significant differences among the tasks. Under monocular vision, significant differences in errors were observed only on the lateral axis. Moreover, we observed that the errors in the lateral and depth axes were proportional to the required movement on these axes under binocular vision and confirmed that the required depth movement under binocular vision determined depth error independent of the other axes. This finding implies that the brain may independently process binocular vision information on each axis. Meanwhile, the required depth movement under monocular vision was independent of performance along the depth axis, indicating an intractable behavior. Our findings highlight the importance of handling depth movement, especially when a virtual reality situation, involving tracking tasks, is generated.

Concurrent attention to hetero-depth surfaces in 3-D visual space is governed by theta rhythm.

When simultaneously confronted with multiple attentional targets, visual system employs a time-multiplexing approach in which each target alternates for prioritized access, a mechanism broadly known as rhythmic attentional sampling. For the past decade, rhythmic attentional sampling has received mounting support from converging behavioral and neural findings. However, so compelling are these findings that a critical test ground has been long overshadowed, namely the 3-D visual space where attention is complicated by extraction of the spatial layout of surfaces extending beyond 2-D planes. It remains unknown how attentional deployment to multiple targets is accomplished in the 3-D space. Here, we provided a time-resolved portrait of the behavioral and neural dynamics when participants concurrently attended to two surfaces defined by motion-depth conjunctions. To characterize the moment-to-moment attentional modulation effects, we measured perceptual sensitivity to the hetero-depth surface motions on a fine temporal scale and reconstructed their neural representations using a time-resolved multivariate inverted encoding model. We found that the perceptual sensitivity to the two surface motions rhythmically fluctuated over time at ~4 Hz, with one's enhancement closely tracked by the other's diminishment. Moreover, the behavioral pattern was coupled with an ongoing periodic alternation in strength between the two surface motion representations in the same frequency. Together, our findings provide the first converging evidence of an attentional "pendulum" that rhythmically traverses different stereoscopic depth planes and are indicative of a ubiquitous attentional time multiplexor based on theta rhythm in the 3-D visual space.

Depth of field expansion method for integral imaging based on diffractive optical element and CNN.

In lens-based display systems, lens aberrations and depth of field (DoF) limitation often lead to blurring and distortion of reconstructed images; Meanwhile, expanding the display DoF will face a trade-off between horizontal resolution and axial resolution, restricting the achievement of high-resolution and large DoF three-dimensional (3D) displays. To overcome these constraints and enhance the DoF and resolution of reconstructed scenes, we propose a DoF expansion method based on diffractive optical element (DOE) optimization and image pre-correction through a convolutional neural network (CNN). This method applies DOE instead of the conventional lens and optimizes DOE phase distribution using the Adam algorithm, achieving depth-invariant and concentrated point spread function (PSF) distribution throughout the entire DoF range; Simultaneously, we utilize a CNN to pre-correct the original images and compensate for the image quality reduction introduced by the DOE. The proposed method is applied to a practical integral imaging system, we effectively extend the DoF of the DOE to 400 mm, leading to a high-resolution 3D display in multiple depth planes. To validate the effectiveness and practicality of the proposed method, we conduct numerical simulations and optical experiments.

Association of Changes in Hip and Knee Kinematics During a Single-Leg Squat With Changes in Patient-Reported Outcomes at 6 Months and 1 Year After Hip Arthroscopy

Background: Previous studies have demonstrated alterations in squat kinematics in patients with femoroacetabular impingement syndrome (FAIS). Little is known about the effects of arthroscopic hip surgery on biomechanics during a single-leg squat (SLS) in these patients. Purpose/Hypothesis: The purpose of this study was to determine if (1) lower extremity dynamic range of motion (ROM) during an SLS task improves after hip arthroscopy for FAIS and (2) correlations exist between changes in patient-reported outcomes (PROs) and changes in lower extremity dynamic ROM during an SLS after hip arthroscopy for FAIS. It was hypothesized that dynamic hip ROM would improve after hip arthroscopy and that hip dynamic ROM would be associated with changes in PRO scores at both 6 months and 1 year. Study Design: Descriptive laboratory study. Methods: Patients with FAIS performed 3 SLSs that were analyzed using a 20-camera motion capture system. Dynamic ROMs were calculated in 3 planes for the hip, knee, ankle, and pelvic segments. Squat depth was calculated as the change in vertical center of mass during the squat cycle. PROs including the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports (HOS–Sports), International Hip Outcome Tool–12, and visual analog scale for pain scores were collected preoperatively and at the time of postoperative testing. Paired-samples t tests were used to compare kinematic variables pre- and postoperatively. Correlations were used to compare changes in PROs with changes in kinematics. All statistical analysis was performed using SPSS Version 26. Results: Fifteen patients were tested preoperatively and at a mean of 9 months postoperatively. All PRO measures improved postoperatively at 6 months and 1 year. Squat depth and sagittal plane hip and knee dynamic ROMs were significantly improved postoperatively. Positive correlations existed between changes in (1) hip ROM with the 6-month HOS-ADL score (r = 0.665) and (2) knee ROM with the 6 month (r = 0.590) and 1-year (r = 0.565) HOS–Sports scores. Conclusion: Dynamic sagittal plane hip and knee ROMs improve after hip arthroscopy for FAIS. These improvements demonstrate strong correlations with improvements in some but not all postoperative PROs. Clinical Relevance: The current study sought to better understand the role of dynamic movement in the diagnosis and treatment of FAIS. These findings indicate that dynamic ROM and squat depth can, similarly to PROs, serve as biomarkers for patient function both before and after hip arthroscopic surgery.

Analysis of the relationship between display depth and 3D image definition in light-field display from visual perspective

An analysis method for the relationship between light-field display (LFD) depth and 3D image definition from visual perspective is presented in this paper. A simplified analytical model suitable for standard LFD system is established, which can be used to analyze the formation of voxels from a perspective that is more consistent with visual perception. Moreover, the formula for calculating voxel size is derived in relation to the depth plane and viewing position. Reasonable simulation programs and LFD devices with different parameters are used in experiments to verify the correctness of the theoretical analysis. The analysis and experimental results presented in this paper may contribute to a better understanding of the principle of light-field display, and it is helpful to design and optimize the LFD system with better display effect.

ARAI-MVSNet: A multi-view stereo depth estimation network with adaptive depth range and depth interval

Multi-View Stereo (MVS) is a fundamental problem in geometric computer vision which aims to reconstruct a scene using multi-view images with known camera parameters. However, the mainstream approaches represent the scene with a fixed all-pixel depth range and equal depth interval partition, which will result in inadequate utilization of depth planes and imprecise depth estimation. In this paper, we present a novel multi-stage coarse-to-fine framework to achieve adaptive all-pixel depth range and depth interval. We predict a coarse depth map in the first stage, then an Adaptive Depth Range Prediction module is proposed in the second stage to zoom in the scene by leveraging the reference image and the obtained depth map in the first stage and predict a more accurate all-pixel depth range for the following stages. In the third and fourth stages, we propose an Adaptive Depth Interval Adjustment module to achieve adaptive variable interval partition for pixel-wise depth range. The depth interval distribution in this module is normalized by Z-score, which can allocate dense depth hypothesis planes around the potential ground truth depth value and vice versa to achieve more accurate depth estimation. Extensive experiments on four widely used benchmark datasets (DTU, TnT, BlendedMVS, ETH 3D) demonstrate that our model achieves state-of-the-art performance and yields competitive generalization ability. Particularly, our method achieves the highest Acc and Overall on the DTU dataset, while attaining the highest Recall and F1-score on the Tanks and Temples intermediate and advanced dataset. Moreover, our method also achieves the lowest e1 and e3 on the BlendedMVS dataset and the highest Acc and F1-score on the ETH 3D dataset, surpassing all listed methods. Project website: https://github.com/zs670980918/ARAI-MVSNet

Camouflage using three-dimensional surface disruption.

Disruptive markings are common in animal patterns and can provide camouflage benefits by concealing the body's true edges and/or by breaking the surface of the body into multiple depth planes. Disruptive patterns that are accentuated by high contrast borders are most likely to provide false depth cues to enhance camouflage, but studies to date have used visual detection models or humans as predators. We presented three-dimensional-printed moth-like targets to wild bird predators to determine whether: (1) three-dimensional prey with disrupted body surfaces have higher survival than three-dimensional prey with continuous surfaces, (2) two-dimensional prey with disruptive patterns or enhanced edge markings have higher survival than non-patterned two-dimensional prey. We found a survival benefit for three-dimensional prey with disrupted surfaces, and a significant effect of mean wing luminance. There was no evidence that false depth cues provided the same protective benefits as physical surface disruption in three-dimensional prey, perhaps because our treatments did not mimic the complexity of patterns found in natural animal markings. Our findings indicate that disruption of surface continuity is an important strategy for concealing a three-dimensional body shape.