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IEEE Transactions on Visualization and... May 2024Spatial User Interfaces along the Reality-Virtuality continuum heavily depend on accurate depth perception. However, current display technologies still exhibit...
Spatial User Interfaces along the Reality-Virtuality continuum heavily depend on accurate depth perception. However, current display technologies still exhibit shortcomings in the simulation of accurate depth cues, and these shortcomings also vary between Virtual or Augmented Reality (VR, AR: eXtended Reality (XR) for short). This article compares depth perception between VR and Video See-Through (VST) AR. We developed a digital twin of an existing office room where users had top erform five depth-dependent tasks in VR and VST AR. Thirty-two participants took part in a user study using a 1 × 4 within-subjects design. Our results reveal higher misjudgment rates in VST AR due to conflicting depth cues between virtual and physical content. Increased head movements observed in participants were interpreted as a compensatory response to these conflicting cues. Furthermore, a longer task completion time in the VST AR condition indicates a lower task performance in VST AR. Interestingly, while participants rated the VR condition as easier and contrary to the increased misjudgments and lower performance with the VST AR display, a majority still expressed a preference for the VST AR experience. We discuss and explain these findings with the high visual dominance and referential power of the physical content in the VST AR condition, leading to a higher spatial presence and plausibility.
PubMed: 38437131
DOI: 10.1109/TVCG.2024.3372061 -
ELife Sep 2023Crowding occurs when the presence of nearby features causes highly visible objects to become unrecognizable. Although crowding has implications for many everyday tasks...
Crowding occurs when the presence of nearby features causes highly visible objects to become unrecognizable. Although crowding has implications for many everyday tasks and the tremendous amounts of research reflect its importance, surprisingly little is known about how depth affects crowding. Most available studies show that stereoscopic disparity reduces crowding, indicating that crowding may be relatively unimportant in three-dimensional environments. However, most previous studies tested only small stereoscopic differences in depth in which disparity, defocus blur, and accommodation are inconsistent with the real world. Using a novel multi-depth plane display, this study investigated how large (0.54-2.25 diopters), real differences in target-flanker depth, representative of those experienced between many objects in the real world, affect crowding. Our findings show that large differences in target-flanker depth increased crowding in the majority of observers, contrary to previous work showing reduced crowding in the presence of small depth differences. Furthermore, when the target was at fixation depth, crowding was generally more pronounced when the flankers were behind the target as opposed to in front of it. However, when the flankers were at fixation depth, crowding was generally more pronounced when the target was behind the flankers. These findings suggest that crowding from clutter outside the limits of binocular fusion can still have a significant impact on object recognition and visual perception in the peripheral field.
Topics: Histological Techniques; Visual Perception
PubMed: 37665324
DOI: 10.7554/eLife.85143 -
Vision Research Sep 2023People with amblyopia demonstrate a reduced ability to judge depth using stereopsis. Our understanding of this deficit is limited, as standard clinical stereo tests may...
People with amblyopia demonstrate a reduced ability to judge depth using stereopsis. Our understanding of this deficit is limited, as standard clinical stereo tests may not be suited to give a quantitative account of the residual stereo ability in amblyopia. In this study we used a stereo test designed specifically for that purpose. Participants identified the location of a disparity-defined odd-one-out target within a random-dot display. We tested 29 amblyopic (3 strabismic, 17 anisometropic, 9 mixed) participants and 17 control participants. We obtained stereoacuity thresholds from 59% of our amblyopic participants. There was a factor of two difference between the median stereoacuity of our amblyopic (103 arcsec) and control (56 arcsec) groups. We used the equivalent noise method to evaluate the role of equivalent internal noise and processing efficiency in amblyopic stereopsis. Using the linear amplifier model (LAM), we determined the threshold difference was due to a greater equivalent internal noise in the amblyopic group (238 vs 135 arcsec), with no significant difference in processing efficiency. A multiple linear regression determined 56% of the stereoacuity variance within the amblyopic group was predicted by the two LAM parameters, with equivalent internal noise predicting 46% alone. Analysis of control group data aligned with our previous work, finding that trade-offs between equivalent internal noise and efficiency play a greater role. Our results allow a better understanding of what is limiting amblyopic performance in our task. We find this to be a reduced quality of disparity signals in the input to the task-specific processing.
Topics: Humans; Amblyopia; Depth Perception; Noise; Vision, Binocular; Vision, Ocular; Visual Acuity; Case-Control Studies
PubMed: 37285783
DOI: 10.1016/j.visres.2023.108267 -
IEEE Transactions on Image Processing :... 20243D perception tasks, such as 3D object detection and Bird's-Eye-View (BEV) segmentation using multi-camera images, have drawn significant attention recently. Despite the...
3D perception tasks, such as 3D object detection and Bird's-Eye-View (BEV) segmentation using multi-camera images, have drawn significant attention recently. Despite the fact that accurately estimating both semantic and 3D scene layouts are crucial for this task, existing techniques often neglect the synergistic effects of semantic and depth cues, leading to the occurrence of classification and position estimation errors. Additionally, the input-independent nature of initial queries also limits the learning capacity of Transformer-based models. To tackle these challenges, we propose an input-aware Transformer framework that leverages Semantics and Depth as priors (named SDTR). Our approach involves the use of an S-D Encoder that explicitly models semantic and depth priors, thereby disentangling the learning process of object categorization and position estimation. Moreover, we introduce a Prior-guided Query Builder that incorporates the semantic prior into the initial queries of the Transformer, resulting in more effective input-aware queries. Extensive experiments on the nuScenes and Lyft benchmarks demonstrate the state-of-the-art performance of our method in both 3D object detection and BEV segmentation tasks.
PubMed: 38236678
DOI: 10.1109/TIP.2024.3352808 -
Biomimetics (Basel, Switzerland) Sep 2023Depth estimation is an ill-posed problem; objects of different shapes or dimensions, even if at different distances, may project to the same image on the retina. Our...
Depth estimation is an ill-posed problem; objects of different shapes or dimensions, even if at different distances, may project to the same image on the retina. Our brain uses several cues for depth estimation, including monocular cues such as motion parallax and binocular cues such as diplopia. However, it remains unclear how the computations required for depth estimation are implemented in biologically plausible ways. State-of-the-art approaches to depth estimation based on deep neural networks implicitly describe the brain as a hierarchical feature detector. Instead, in this paper we propose an alternative approach that casts depth estimation as a problem of active inference. We show that depth can be inferred by inverting a hierarchical generative model that simultaneously predicts the eyes' projections from a 2D belief over an object. Model inversion consists of a series of biologically plausible homogeneous transformations based on Predictive Coding principles. Under the plausible assumption of a nonuniform fovea resolution, depth estimation favors an active vision strategy that fixates the object with the eyes, rendering the depth belief more accurate. This strategy is not realized by first fixating on a target and then estimating the depth; instead, it combines the two processes through action-perception cycles, with a similar mechanism of the saccades during object recognition. The proposed approach requires only local (top-down and bottom-up) message passing, which can be implemented in biologically plausible neural circuits.
PubMed: 37754196
DOI: 10.3390/biomimetics8050445 -
International Journal of Women's Health 2023Gender-based perceptions about maternal health care during pregnancy draw attention to the existence of gender inequity in maternal health care. This study aimed to...
PURPOSE
Gender-based perceptions about maternal health care during pregnancy draw attention to the existence of gender inequity in maternal health care. This study aimed to understand the gender-based perception of gender roles and norms, gender relations, social support, and psychosocial variation in maternal health care during pregnancy.
METHODS
A qualitative study was conducted in three rural districts of Jimma, Ethiopia. Participants were purposefully chosen from the community groups, including male and female health development armies, religious leaders, health extension workers, midwifery nurses, and primary health care unit directors. The data was gathered through in-depth interviews and focus group discussions. The actual data was collected by men and women qualitative study experts. Atlas ti Ver 9 was used for the analysis. The data was initially coded then changed to a sub-category and at last converted to a category.
RESULTS
Four categories emerged: Gender-based roles and norms, psychosocial variation, social support, and gender relations. The informants described men's and women's independent and shared roles improve maternal health care service usage during pregnancy. Once the women became pregnant, men undertook a variety of demanding duties to enhance maternity service consumption. Gender relations and shared decision-making were essential in facilitating maternal healthcare utilization during pregnancy and beyond.
CONCLUSION
This study revealed that maternal health care should not be limited to women alone. Men's and women's prior maternal health experiences, in addition to their knowledge and beliefs, have significantly impacted the utilization of maternal healthcare services during pregnancy. Policymakers and academics should consider men's essential contribution to maternal health care during pregnancy. However, in order to increase their intention to use maternal health care services, it is necessary to clearly identify the interests of women in which men should be involved.
PubMed: 37849848
DOI: 10.2147/IJWH.S418653 -
BMC Pregnancy and Childbirth Feb 2024A significant concern for Bangladesh is the high prevalence of adolescent pregnancy and the associated negative consequences for mother and baby, including a...
BACKGROUND
A significant concern for Bangladesh is the high prevalence of adolescent pregnancy and the associated negative consequences for mother and baby, including a teen-related increased risk of preterm birth (PTB). Bangladesh also has one of the highest incidences of PTB (19%). Despite these high numbers of adolescent pregnancies and PTB, little is reported about the experiences of adolescent mothers in caring for their preterm babies, and the interventions needed to support them. The aim of this study was to explore gaps and opportunities for improved care for preterm babies among adolescent mothers and communities in rural Bangladesh.
METHODS
We conducted a qualitative study in rural villages of Baliakandi sub-district of Bangladesh. Data collection involved in-depth interviews with adolescent mothers of premature and term babies, adult mothers with premature babies, and family members (n = 36); focus groups with community members (n = 5); and key informant interviews with healthcare providers (n = 13). Adolescent mothers with term and adult mothers with PTBs were included to elicit similarities and differences in understanding and care practices of PTB. A thematic approach was used for data analysis.
RESULTS
We explored two major themes- perceptions and understanding of PTB; care practices and care-seeking for illnesses. We observed gaps and variations in understanding of preterm birth (length of gestation, appearance, causes, problems faced) and care practices (thermal management, feeding, weight monitoring) among all, but particularly among adolescents. Immediate natal and marital-kins were prominent in the narratives of adolescents as sources of informational and instrumental support. The use of multiple providers and delays in care-seeking from trained providers for sick preterm babies was noted, often modulated by the perception of severity of illness, cost, convenience, and quality of services. Health systems challenges included lack of equipment and trained staff in facilities to provide special care to preterm babies.
CONCLUSION
A combination of factors including local knowledge, socio-cultural practices and health systems challenges influenced knowledge of, and care for, preterm babies among adolescent and adult mothers. Strategies to improve birth outcomes will require increased awareness among adolescents, women, and families about PTB and improvement in quality of PTB services at health facilities.
Topics: Pregnancy; Infant; Adult; Adolescent; Infant, Newborn; Female; Humans; Premature Birth; Adolescent Mothers; Bangladesh; Infant, Premature; Mothers; Perception
PubMed: 38368364
DOI: 10.1186/s12884-024-06345-x -
Omega Aug 2023The aim of this study is to explore intensive care nurses' perceptions and experiences about death and dying patient. This study included 15 nurses from a university...
The aim of this study is to explore intensive care nurses' perceptions and experiences about death and dying patient. This study included 15 nurses from a university hospital's intensive care units (paediatric and internal medicine). Data were collected through face-to-face, in-depth and individual interviews using the "Nurse Information Form" and "Semi-Structured Interview Form". Six major themes and sixteen sub-themes were identified on the nurses' perceptions and experiences with death. After the nurses described their perceptions of death, their responses, approaches, coping mechanisms, and effects on the dead and dying patient in care and factors affecting perceptions of death were defined. Our findings suggest that nurses, particularly those working in intensive care, should be educated/trained on death, and dying patient care. Thus, orderly psychological support should be provided to nurses.
PubMed: 37605481
DOI: 10.1177/00302228231198575 -
Scientific Reports Jul 2023Pulse-coupled neural networks perform well in many fields such as information retrieval, depth estimation and object detection. Based on pulse coupled neural network...
Pulse-coupled neural networks perform well in many fields such as information retrieval, depth estimation and object detection. Based on pulse coupled neural network (PCNN) theory, this paper constructs a visual perception model framework and builds a real image reproduction platform. The model firstly analyzes the structure and generalization ability of neural network multi-class classifier, uses the minimax criterion of feature space as the splitting criterion of visual perception decision node, which solves the generalization problem of neural network learning algorithm. In the simulation process, the initial threshold is optimized by the two-dimensional maximum inter-class variance method, and in order to improve the real-time performance of the algorithm, the fast recurrence formula of neural network is derived and given. The PCNN image segmentation method based on genetic algorithm is analyzed. The genetic algorithm improves the loop termination condition and the adaptive setting of model parameters of PCNN image segmentation algorithm, but the PCNN image segmentation algorithm still has the problem of complexity. In order to solve this problem, this paper proposed an IGA-PCNN image segmentation method combining the improved algorithm and PCNN model. Firstly, it used the improved immune genetic algorithm to adaptively obtain the optimal threshold, and then replaced the dynamic threshold in PCNN model with the optimal threshold, and finally used the pulse coupling characteristics of PCNN model to complete the image segmentation. From the coupling characteristics of PCNN, junction close space of image and gray level characteristics, it determined the local gray mean square error of image connection strength coefficient. The feature extraction and object segmentation properties of PCNN come from the spike frequency of neurons, and the number of neurons in PCNN is equal to the number of pixels in the input image. In addition, the spatial and gray value differences of pixels should be considered comprehensively to determine their connection matrix. Digital experiments show that the multi-scale multi-task pulse coupled neural network model can shorten the total training time by 17 h, improve the comprehensive accuracy of the task test data set by 1.04%, and shorten the detection time of each image by 4.8 s compared with the series network model of multiple single tasks. Compared with the traditional PCNN algorithm, it has the advantages of fast visual perception and clear target contour segmentation, and effectively improves the anti-interference performance of the model.
PubMed: 37507535
DOI: 10.1038/s41598-023-39376-z -
Scientific Reports Mar 2024Depth perception is crucial in human vision, allowing us to move and interact with our 3-D surroundings. We used a stereoscopic transparent stimulus comprising parallel...
Depth perception is crucial in human vision, allowing us to move and interact with our 3-D surroundings. We used a stereoscopic transparent stimulus comprising parallel overlapping transparent stereoscopic surfaces (POTS) to understand depth perception better. The study focused on exploring the effect of a surrounding frame on the perceived depth of a POTS configuration. The research was based on a proposed idea that explains an "off-frame" effect: a frame at a different depth from a 2-D photograph depicting a 3-D scene increases its apparent depth qualitatively. The idea assumes that processing the disparity between a frame and a photo reduces the reliability of the photograph's flatness cues and increases depth magnitude in depth cue integration. We examined whether the idea can be applied to a 3-D POTS with the flatness cue as the constant accommodation. Through three experiments, the study showed that frames impact the perceived depth magnitude of a POTS configuration. More specifically, the depth magnitude increases as the frame's disparity concerning the monitor plane increases and decreases as the frame's size increases. We discussed the results in the context of depth cue combination.
PubMed: 38509233
DOI: 10.1038/s41598-024-57283-9