Disparity Adjustment Research Articles

Age and sex-related differences in outcomes of OHCA patients after adjustment for sex-based in-hospital management disparities

ObjectivesOut-of-hospital cardiac arrest (OHCA) survival differences due to sex remain controversial. Previous studies adjusted for prehospital variables, but not sex-based in-hospital management disparities. We aimed to investigate age and sex-related differences in survival outcomes in OHCA patients after adjustment for sex-based in-hospital management disparities. MethodsThis retrospective observational study used a prospective multicenter OHCA registry to review data of patients from October 2015 to December 2020. The primary outcome was good neurological outcome defined as cerebral performance category score 1 or 2. We performed multivariable logistic regression and restricted cubic spline analysis according to age. ResultsTotally, 8988 patients were analyzed. Women showed poorer prehospital characteristics and received fewer coronary angiography, percutaneous coronary interventions, targeted temperature management, and extracorporeal membrane oxygenation than men. Good neurological outcomes were lower in women than in men (5.8% vs. 12.2%, p < 0.001). After adjustment for age, prehospital variables, and in-hospital management, women were more likely to have good neurological outcomes than men (adjusted odds ratio [aOR] 1.37, 95% confidence interval [CI] 1.07–1.74, p = 0.012). The restricted cubic spline curve showed a reverse sigmoid pattern of adjusted predicted probability of outcomes and dynamic associations of sex and age-based outcomes. ConclusionsWomen with OHCA were more likely to have good neurological outcome after adjusting for age, prehospital variables, and sex-based in-hospital management disparities. There were non-linear associations between sex and survival outcomes according to age and age-related sex-based differences.

Dynparity: Dynamic disparity adjustment to avoid stereo window violations on stationary stereoscopic displays

AbstractWe propose a novel method to avoid stereo window violations at screen borders. These occur for objects in front of the zero parallax plane, which appear in front of the (physical) screen, and that are clipped for one eye while still being visible for the other eye. This contradicts other stereo cues, particularly disparity, potentially resulting in eye strain and simulator sickness. In interactive and dynamic virtual environments, where the user controls the camera, for example, via head tracking, it is impossible to avoid stereo window violations completely. We propose Dynparity, a novel rendering method to eliminate the conflict between clipping and negative disparity, by introducing a nonuniform stereoscopic projection. For each vertex in front of the zero parallax plane, we compute the stereoscopic projection such that the parallax approaches zero toward the edge of the screen. Our approach works entirely on the GPU in real‐time and can be easily included in modern game engines. We conducted a user study comparing our method to the standard stereo projection on a large‐screen stereo wall with head tracking. Our results show significantly reduced simulator sickness when using Dynparity compared to the standard stereo rendering.

Stereoscopic image stitching with rectangular boundaries

This paper proposes a novel algorithm for stereoscopic image stitching, which aims to produce stereoscopic panoramas with rectangular boundaries. As a result, it provides wider field of view and better viewing experience for users. To achieve this, we formulate stereoscopic image stitching and boundary rectangling in a global optimization framework that simultaneously handles feature alignment, disparity consistency and boundary regularity. Given two (or more) stereoscopic images with overlapping content, each containing two views (for left and right eyes), we represent each view using a mesh and our algorithm contains three main steps: We first perform a global optimization to stitch all the left views and right views simultaneously, which ensures feature alignment and disparity consistency. Then, with the optimized vertices in each view, we extract the irregular boundary in the stereoscopic panorama, by performing polygon Boolean operations in left and right views, and construct the rectangular boundary constraints. Finally, through a global energy optimization, we warp left and right views according to feature alignment, disparity consistency and rectangular boundary constraints. To show the effectiveness of our method, we further extend our method to disparity adjustment and stereoscopic stitching with large horizon. Experimental results show that our method can produce visually pleasing stereoscopic panoramas without noticeable distortion or visual fatigue, thus resulting in satisfactory 3D viewing experience.

Disparity Adjustment Method based on Disparity Enhancement inside Objects and its Evaluation

Disparity Adjustment Method based on Disparity Enhancement inside Objects and its Evaluation

Toward Simultaneous Visual Comfort and Depth Sensation Optimization for Stereoscopic 3-D Experience.

Visual comfort and depth sensation are two important incongruent counterparts in determining the overall stereoscopic 3-D experience. In this paper, we proposed a novel simultaneous visual comfort and depth sensation optimization approach for stereoscopic images. The main motivation of the proposed optimization approach is to enhance the overall stereoscopic 3-D experience. Toward this end, we propose a two-stage solution to address the optimization problem. In the first layer-independent disparity adjustment process, we iteratively adjust the disparity range of each depth layer to satisfy with visual comfort and depth sensation constraints simultaneously. In the following layer-dependent disparity process, disparity adjustment is implemented based on a defined total energy function built with intra-layer data, inter-layer data and just noticeable depth difference terms. Experimental results on perceptually uncomfortable and comfortable stereoscopic images demonstrate that in comparison with the existing methods, the proposed method can achieve a reasonable performance balance between visual comfort and depth sensation, leading to promising overall stereoscopic 3-D experience.

Content-aware disparity adjustment for different stereo displays

In this paper, we present an effective disparity mapping method for binocular stereoscopic image. It is inspired by the observation that its displayed depth would change, when a stereoscopic image is displayed on different size screens. The phenomenon may bring an uncomfortable experience for viewers. To make a comfortable stereoscopic image for viewers, moreover to adapt a stereoscopic image to a target display screen, we propose a content-aware disparity adjustment method. Firstly, the disparity mapping is established to control and retarget the depth of a stereoscopic scene. Then, the relationship between the disparity editing and image content editing is established to guide the proposed warping model. At last, to implement the disparity mapping operator, we propose a content-aware stereoscopic mesh warping model, which can simultaneously avoid the salient region distortion and adjust disparity to a target range by establishing the relationship. Experimental results show that the proposed method can effectively adjust disparity of stereoscopic image, which not only avoids the salient region distortion and adjusts disparity to a target range.

Comfort-driven disparity adjustment for stereoscopic video

Pixel disparity—the offset of corresponding pixels between left and right views—is a crucial parameter in stereoscopic three-dimensional (S3D) video, as it determines the depth perceived by the human visual system (HVS). Unsuitable pixel disparity distribution throughout an S3D video may lead to visual discomfort. We present a unified and extensible stereoscopic video disparity adjustment framework which improves the viewing experience for an S3D video by keeping the perceived 3D appearance as unchanged as possible while minimizing discomfort. We first analyse disparity and motion attributes of S3D video in general, then derive a wide-ranging visual discomfort metric from existing perceptual comfort models. An objective function based on this metric is used as the basis of a hierarchical optimisation method to find a disparity mapping function for each input video frame. Warping-based disparity manipulation is then applied to the input video to generate the output video, using the desired disparity mappings as constraints. Our comfort metric takes into account disparity range, motion, and stereoscopic window violation; the framework could easily be extended to use further visual comfort models. We demonstrate the power of our approach using both animated cartoons and real S3D videos.

対象内部の視差を強調する視差調整手法と評価

対象内部の視差を強調する視差調整手法と評価

Boundary-preserving stereo matching with certain region detection and adaptive disparity adjustment

In this paper, we propose boundary-preserving stereo matching using certain region detection and adaptive disparity adjustment. The main contribution of the proposed method lies in the detection and adjustment of incorrect disparities. In the detection process, we detect certain regions in initial disparity maps to distinguish errors in disparity caused by the disparity discontinuity. In the adjustment process, we adjust the disparity map to reduce the adverse effect of errors in disparity using the certain region detection results. Based on the color similarity, spatial distance, and the reliability of the certain and uncertain regions, we set an adaptive support-weight to each pixel for adjusting the accuracy. Experimental results demonstrate that the proposed method produces high-quality disparity maps by successfully preserving disparity discontinuities along the object boundaries.

Crosstalk reduction in stereoscopic 3D displays: Disparity adjustment using crosstalk visibility index for crosstalk cancellation

Stereoscopic displays provide viewers with a truly fascinating viewing experience. However, current stereoscopic displays suffer from crosstalk that is detrimental to image quality, depth quality, and visual comfort. In order to reduce the perceived crosstalk in stereoscopic displays, this paper proposes a crosstalk reduction method that combines disparity adjustment and crosstalk cancellation. The main idea of the proposed method is to displace the visible crosstalk using the disparity adjustment in a way that less amounts of intensity leakage occur on perceptually important regions in a scene. To this purpose, we estimate a crosstalk visibility index map for the scene that represents pixel-by-pixel importance values associated with the amount of perceived crosstalk and negative-after-effects of the crosstalk cancellation. Based on the crosstalk visibility index, we introduce a new disparity adjustment method that reduces the annoying crosstalk in processed images, which is followed by the crosstalk cancellation. The effectiveness of the proposed method has been successfully evaluated by subjective assessments of image quality and viewing preference. Experimental results demonstrate that the proposed method effectively improves the image quality and overall viewing quality of stereoscopic videos.

A Trinocular Stereo-Matching Algorithm Based on Adaptive Support-Weight for Mobile Service Robot

A trinocular stereo-matching algorithm based on adaptive support-weight and disparity adjustment has been proposed to improve the accuracy of trinocular vision. Adaptive support-weight which is an efficient window selection method in binocular stereo is applied in the trinocular stereo. A robust target image selection method is also proposed for using the information of different target images in trinocular stereo-vision system efficiently. So occlusion can be handled well by this means. The vision system is tested in the project Family Life Support Multi-Robot Systems.

A Stereo Matching Algorithm with Support Regions Based on Color and Texture Estimate

A stereo matching algorithm with support regions based on color and texture estimate is proposed. Firstly, the initial support regions are selected from the image according to the distribution of the quantized color labels. Then, the texture similarity is used to determine the arm length growing and combine adjacent regions. The accurate support regions are obtained. Thirdly, the support weight is introduced under the constraint of support region. Finally, the initial disparity can be corrected by using disparity adjustment method until a reasonable disparity map is obtained. The experimental results show that the good disparity result can be obtained.

Impact of admission month and hospital teaching status on outcomes in subarachnoid hemorrhage: evidence against the July effect

The authors sought to identify the presence of a "July effect," a transient increase in adverse outcomes during July, among a cohort of spontaneous subarachnoid hemorrhage (SAH) admissions recorded in the National Inpatient Sample (NIS). The discharge status, admission month, patient demographics, treatment parameters, and hospital characteristics among spontaneous SAH admissions were extracted from the 2001-2008 NIS. Multivariate regression was used to determine whether an unfavorable discharge status and/or in-hospital mortality significantly increased in summer months in a pattern suggestive of a July effect. Additional models were generated to assess the impact of hospital teaching status on these outcomes. Among 57,663,486 hospital admissions from the 2001-2008 NIS, 52,879 cases of spontaneous SAH (ICD-9-CM 430) were treated at teaching (36,914 cases [70%]) and nonteaching (15,965 cases [30%]) facilities. Regression models failed to reveal a July effect for in-hospital mortality (χ(2) = 0.75, p = 1.000) or unfavorable discharges (χ(2) = 1.69, p = 0.999) among monthly SAH admissions, although they did suggest a significant reduction in these outcomes (in-hospital mortality, OR = 0.89, p < 0.001; unfavorable discharges, OR = 0.88, p < 0.001) among teaching hospitals as compared with nonteaching hospitals after adjustment for disparities in demographic, treatment, and hospital characteristics. The discharge disposition among SAH admissions within the NIS was not suggestive of a July effect but did reveal that teaching institutions have significantly lower rates of adverse outcomes when compared with nonteaching hospitals. Note, however, that the origins of this difference related to teaching status remain unclear.

A Single Image Representation Model for Efficient Stereoscopic Image Creation

Computer graphics is one of the most efficient ways to create a stereoscopic image. The process of stereoscopic CG generation is, however, still very inefficient compared to that of monoscopic CG generation. Despite that stereo images are very similar to each other, they are rendered and manipulated independently. Additional requirements for disparity control specific to stereo images lead to even greater inefficiency. This paper proposes a method to reduce the inefficiency accompanied in the creation of a stereoscopic image. The system automatically generates an optimized single image representation of the entire visible area from both cameras. The single image can be easily manipulated with conventional techniques, as it is spatially smooth and maintains the original shapes of scene objects. In addition, a stereo image pair can be easily generated with an arbitrary disparity setting. These convenient and efficient features are achieved by the automatic generation of a stereo camera pair, robust occlusion detection with a pair of Z-buffers, an optimization method for spatial smoothness, and stereo image pair generation with a non-linear disparity adjustment. Experiments show that our technique dramatically improves the efficiency of stereoscopic image creation while preserving the quality of the results.

Stereo panorama acquisition and automatic image disparity adjustment for stereoscopic visualization

Image-based visualization is popular for various virtual tour applications, due to high-quality photorealism or simplicity for rendering. Stereo panorama representations of the virtual world are already a common part of this, either in small (computer screen) format or on large-scale stereo displays or screens. This paper discusses methods for determining optimum parameters, both for high-accuracy stereo panoramic image recording and displaying, with a special focus on automatic image disparity enhancement while displaying (e.g., including zooming) a stereo panorama. Experiments show that the discussed parameters are indeed critical for ensuring high-quality stereo viewing. Derived formulas in this study are applicable to various kinds of technologies for stereo panorama imaging or stereoscopic displaying.

三目自适应权值立体匹配和视差校准算法

三目自适应权值立体匹配和视差校准算法

Dynamic disparity adjustment and histogram-based filtering of range data for fast 3-D hand tracking

Range data is very important in human-computer interaction applications. Although less costly, range acquisition and processing still presents a speed vs data reliability tradeoff. This paper proposes a method that, given noisy and generally unreliable range data, can filter out erroneous information using range histograms for regions of interest selected in registered color data. Then, using the resulting consistent data that has passed filters, this method limits the depth search space dynamically using motion history and its current state. Experimental results demonstrate the success of the proposed algorithm. Using filtered range data, the algorithm correctly identified the hand involved in manipulation 99.85% of the time. Dynamic disparity adjustment produced a speedup of 60.17% over a static disparity range selection. An application to virtual reality navigation is also presented.

Role Taking and Self-Image Disparity: A Further Test of Cognitive-Developmental Thought

34 seventh graders were assigned to two groups according to developmental level as defined by role-taking ability. High role-takers exhibited greater self-image disparity than low role-takers. The data support the developmental formulation that self-image disparity is positively related to developmental status. These findings indicate a positive rather than an ominous relation between self-image disparity and psychological adjustment.

Regional Disparity, Migration and Economic Adjustment: A Reappraisal

The object of this paper is to reconsider the role of migration in the creation (or prevention) of regional economic disparities. We define regional disparity as sustained geographic differences in per capita income, wage rates and/or unemployment. Our point of reference is what is often called the neoclassical model of regional economic adjustment, which posits that migration generally has a dampening effect on regional economic disparities. We assume that the reader is basically familiar with the arguments underlying this model, whose policy implications for Canada have recently been outlined by Courchene (1978). We shall attempt to show that the impact of migration on regional disparity may be far less certain than is often assumed. Our reappraisal is in the form of a general (non-mathematical) discussion, focusing on certain theoretical and conceptual dimensions surrounding much of the debate on the role of migration in regional development. The thrust of this paper, as the reader will discover, is on the regional growth process, or in other words, on the long-term determinants of regional labour demand. As we shall attempt to show, the manner in which we approach the dimensions of time and space may significantly affect our reasoning on this subject. We do not propose to test a new model. Some empirical evidence is presented to support our case; unless otherwise indicated, results are based on Polese (1978) and Polese and Leminh (1978).1