Kinetic Depth Research Articles

Reconstructing a disambiguation sequence that forms perceptual memory of multistable displays via reverse correlation method: Bias onset perception but gently.

When multistable displays are presented intermittently with long blank intervals, their onset perception is determined by perceptual memory of multistable displays. We investigated when and how it is formed using a reverse correlation method and bistable kinetic depth effect displays. Each experimental block consisted of interleaved fully ambiguous probe and exogenously disambiguated prime displays. The purpose of the former was to "read out" the perceptual memory, whereas the latter contained purely random disambiguation sequences that were presented at the beginning of the prime display, throughout the entire presentation, or at the beginning and the end of the presentation. For each experiment and condition, we selected a subset of trials with disambiguation sequences that led to a change in perception of either the prime itself (sequences that modified perception) or the following fully ambiguous probe (sequences that modified perceptual memory). We estimated average disambiguation sequences for each participant using additive linear models. We found that an optimal sequence started at the onset with a moderate disambiguation against the previously dominant state (dominant perception for the previous probe) that gradually reduced until the display is fully ambiguous. We also show that the same sequence leads to an altered perception of the prime, indicating that perception and perceptual memory form at the same time. We suggest that perceptual memory is a consequence of an earlier evidence accumulation process and is informative about how the visual system treated ambiguity in the past rather than how it anticipates an uncertain future.

Association between Cerebral Coordination Functions and Clinical Outcomes of Alzheimer's Dementia.

Background: Alzheimer’s dementia (AD) is a degenerative disease that impairs cognitive function, initially, and then motor or other function, eventually. Motor coordination function impairment usually accompanies cognition impairment but it is seldom examined whether it can reflect the clinical outcomes of AD. Methods: 113 clinically diagnosed AD patients with a mean age of 78.9 ± 6.9 years underwent an annual neuropsychological assessment using the Mini-Mental State Examination (MMSE), the Cognitive Abilities Screening Instrument (CASI), the Sum of Boxes of Clinical Dementia Rating (CDR-SB), and the CDR. The cerebral coordination function was evaluated through correlations among 15 joints with a kinetic depth sensor annually. An intra-individual comparison of both cognitive and motor coordination functions was performed to examine their correlations. Results: The changes in coordination function in the lower limbs can significantly reflect the clinical outcomes, MMSE (p < 0.001), CASI (p = 0.006), CDR (p < 0.001), and CDR-SB (p < 0.001), but the changes in upper limbs can only reflect the clinical outcome in CDR (p < 0.001). Conclusions: The use of a kinetic depth sensor to determine the coordination between joints, especially in lower limbs, can significantly reflect the global functional and cognitive outcomes in AD. Such evaluations could be another biomarker used to evaluate non-cognitive outcomes in AD for clinical and research purposes.

Quantifying evolving toxicity in the TAML/peroxide mineralization of propranolol.

SummaryOxidative water purification of micropollutants (MPs) can proceed via toxic intermediates calling for procedures for connecting degrading chemical mixtures to evolving toxicity. Herein, we introduce a method for projecting evolving toxicity onto composite changing pollutant and intermediate concentrations illustrated through the TAML/H2O2 mineralization of the common drug and MP, propranolol. The approach consists of identifying the key intermediates along the decomposition pathway (UPLC/GCMS/NMR/UV-Vis), determining for each by simulation and experiment the rate constants for both catalytic and noncatalytic oxidations and converting the resulting predicted concentration versus time profiles to evolving composite toxicity exemplified using zebrafish lethality data. For propranolol, toxicity grows substantially from the outset, even after propranolol is undetectable, echoing that intermediate chemical and toxicity behaviors are key elements of the environmental safety of MP degradation processes. As TAML/H2O2 mimics mechanistically the main steps of peroxidase catalytic cycles, the findings may be relevant to propranolol degradation in environmental waters.

3D computational modeling and perceptual analysis of kinetic depth effects

Humans have the ability to perceive kinetic depth effects, i.e., to perceived 3D shapes from 2D projections of rotating 3D objects. This process is based on a variety of visual cues such as lighting and shading effects. However, when such cues are weak or missing, perception can become faulty, as demonstrated by the famous silhouette illusion example of the spinning dancer. Inspired by this, we establish objective and subjective evaluation models of rotated 3D objects by taking their projected 2D images as input. We investigate five different cues: ambient luminance, shading, rotation speed, perspective, and color difference between the objects and background. In the objective evaluation model, we first apply 3D reconstruction algorithms to obtain an objective reconstruction quality metric, and then use quadratic stepwise regression analysis to determine weights of depth cues to represent the reconstruction quality. In the subjective evaluation model, we use a comprehensive user study to reveal correlations with reaction time and accuracy, rotation speed, and perspective. The two evaluation models are generally consistent, and potentially of benefit to inter-disciplinary research into visual perception and 3D reconstruction.

Hairy Slices II: Depth Cues for Visualizing 3D Streamlines Through Cutting Planes

AbstractVisualizing 3D vector fields is challenging because of occlusion problems and the difficulty of providing depth cues that adequately support the perception of direction of flow lines in 3D space. One of the depth cues that has proven most valuable for the perception of other kinds of 3D data, notably 3D networks and 3D point clouds, is structure‐from‐motion (also called the Kinetic Depth Effect); another powerful depth cue is stereoscopic viewing. We carried out an experiment of the perception of direction for short streamlines passing through a cutting plane. The conditions included viewing with and without structure‐from‐motion and with and without stereoscopic depth. Conditions also include comparing streamtubes to lines. The results show that for this particular task, stereo provided an effective depth cue, but structure‐from‐motion did not. Ringed streamtubes and streamcones provided good 3D direction information, even without stereoscopic viewing. We conclude with guidelines for viewing slices through vector fields.

Surface curvature from kinetic depth can affect lightness.

The light reaching the eye confounds the proportion of light reflected from surfaces in the environment with their illumination. To achieve constancy in perceived surface reflectance (lightness) across variations in illumination, the visual system must infer the relative contribution of reflectance to the incoming luminance signals. Previous studies have shown that contour and stereo cues to surface shape can affect the lightness of sawtooth luminance profiles. Here, we investigated whether cues to surface shape provided solely by motion (via the kinetic depth effect) can similarly influence lightness. Human observers judged the relative brightness of patches contained within abutting surfaces with identical luminance ramps. We found that the reported brightness differences were significantly lower when the kinetic depth effect supported the impression of curved surfaces, compared to similar conditions without the kinetic depth effect. This demonstrates the capacity of the visual system to use shape from motion to "explain away" alternative interpretations of luminance gradients, and supports the cue-invariance of the interaction between shape and lightness. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The visual kinetic depth effect is altered with Parkinson's disease

The visual kinetic depth effect is altered with Parkinson's disease

The Contribution of Stereoscopic and Motion Depth Cues to the Perception of Structures in 3D Point Clouds

Particle-based simulations are used across many science domains, and it is well known that stereoscopic viewing and kinetic depth enhance our ability to perceive the 3D structure of such data. But the relative advantages of stereo and kinetic depth have not been studied for point cloud data, although they have been studied for 3D networks. This article reports two experiments assessing human ability to perceive 3D structures in point clouds as a function of different viewing parameters. In the first study, the number of discrete views was varied to determine the extent to which smooth motion is needed. Also, half the trials had stereoscopic viewing and half had no stereo. The results showed kinetic depth to be more beneficial than stereo viewing in terms of accuracy and so long as the motion was smooth. The second experiment varied the amplitude of oscillatory motion from 0 to 16 degrees. The results showed an increase in detection rate with amplitude, with the best amplitudes being 4 degrees and greater. Overall, motion was shown to yield greater accuracy, but at the expense of longer response times in comparison with stereoscopic viewing.

Supplemental Material for Surface Curvature From Kinetic Depth Can Affect Lightness

Supplemental Material for Surface Curvature From Kinetic Depth Can Affect Lightness

The End of Reconstruction, Again: Dylann Roof, Thomas Dixon Jr., and the Transhistorical Structures of Racist Feeling

The End of Reconstruction, Again:Dylann Roof, Thomas Dixon Jr., and the Transhistorical Structures of Racist Feeling Gordon Fraser (bio) On the night of Barack Obama's election to the presidency, the New York Times columnist Thomas Friedman expressed an understandable hopefulness about the future of race relations. "Breaking with our racial past," he predicted, would be the "least" of our problems. Friedman closed his column with words that bridged the troubled past and the hopeful future. "The Civil War is over," he wrote. "Let reconstruction begin."1 Yet by invoking the Civil War and Reconstruction, [End Page 174] Friedman identified a more complicated history than he may have intended. Reconstruction had been a political experiment, conducted between 1865 and 1877, in which the Congress of the United States attempted to enforce legal and civic equality across race in the former Confederate states. For a brief moment, it seemed to work. By 1887, for instance, seventeen African Americans had been elected or appointed to Congress.2 But according to observers as diverse as William Dunning and W. E. B. Du Bois, the experiment failed.3 Thousands were lynched as multi-racial city, county, and state governments were overthrown in white supremacist coups d'état.4 The United States would witness a century of de jure racial apartheid, followed by the lingering de facto segregation of today. Like the civil rights era (1948–1970), Reconstruction constituted what Michael Omi and Howard Winant have called a "great [moment] of … mainstream political upsurge." Backlash followed both periods.5 We are witnessing a similar backlash today: an energized racism overlapping with and subsequent to the administration of the first black president and the renewal of emancipatory movements for justice. The emergence of white supremacist militias in city centers has forced all but the most craven to acknowledge that racism is resurgent in US political life. To push Friedman's metaphor just a bit further: If Obama's election ushered in a "reconstruction," then we in the aftermath of the Obama administration should be extraordinarily cautious about what came after the first Reconstruction: Plessy v. Ferguson, the Wilmington political coup, and Jim Crow. I raise the specter of Reconstruction's long aftermath not to conflate its historical particularity with that of the present but rather to suggest that historical parallels might enable us to think about the structural operations of racism. We need to understand, I think, not simply how US society enables racial despotism but how the experience of that despotism by its ostensible beneficiaries enables its reinvigoration. We need a scholarship not simply of race but of racism. Such a scholarship might begin, I think, by reading newly resurgent racisms as structures of feeling. As formulated by Raymond Williams half a century ago, structures of feeling offer an analytic for explaining messy, even incoherent, systems of belief. As lived and expressed, such structures appear more often as "a latency" across and between formal ideologies.6 Williams explains: "The new generation responds in its own ways to the unique world it is inheriting, taking up many continuities, that can be traced, … yet feeling its whole life in certain ways differently, and shaping its [End Page 175] creative response into a new structure of feeling."7 While social, legal, and political structures might pass from generation to generation relatively intact, structures of feeling, partly articulated and even internally contradictory, are invented anew. I suggest that understanding racism as such a structure would enable us to confront its four primary vectors—racial terrorism, state violence, reactionary politics, and exclusionary laws—not as a coherent project to be contested ideologically but a cluster of latent, even contradictory, potentials. We might begin exploring such structures of racist feeling in Shelby, North Carolina. Dylann Roof, who would be convicted of murdering nine people in the Emanuel African Methodist Episcopal Church in Charleston, was arrested in Shelby. When Roof was captured in June 2015, a news report described his appearance in the small community as "unlikely."8 Perhaps it was. But the town, like the AME Church of Charleston itself, offers kinetic depth to an observer with a sense of history. Shelby was also the childhood home of the...

Aging and visual 3-D shape recognition from motion.

Two experiments were conducted to evaluate the ability of younger and older adults to recognize 3-D object shape from patterns of optical motion. In Experiment 1, participants were required to identify dotted surfaces that rotated in depth (i.e., surface structure portrayed using the kinetic depth effect). The task difficulty was manipulated by limiting the surface point lifetimes within the stimulus apparent motion sequences. In Experiment 2, the participants identified solid, naturally shaped objects (replicas of bell peppers, Capsicum annuum) that were defined by occlusion boundary contours, patterns of specular highlights, or combined optical patterns containing both boundary contours and specular highlights. Significant and adverse effects of increased age were found in both experiments. Despite the fact that previous research has found that increases in age do not reduce solid shape discrimination, our current results indicated that the same conclusion does not hold for shape identification. We demonstrated that aging results in a reduction in the ability to visually recognize 3-D shape independent of how the 3-D structure is defined (motions of isolated points, deformations of smooth optical fields containing specular highlights, etc.).

The visual kinetic depth effect is altered with Parkinson's disease

BackgroundPeople with Parkinson's disease (PD) often have visual-perceptual disorders. The goal of this study was to learn if they can develop a three dimensional (3D) percept that depends on the kinetic depth effect; that is, the viewer's ability to spatially integrate over time images that are moving along many trajectories. MethodsSixteen patients with PD and 12 healthy matched controls were presented with stimuli that were comprised of a circular region of randomly placed dots that moved as orthographic projections of a sphere. With a normal kinetic depth effect, the Training stimuli appear as an opaque rotating ball and the Test stimuli appear as a rotating transparent ball. ResultsWhereas all controls and all PD patients reported seeing the Training stimuli as a rotating ball, the patients with PD were significantly less likely to report the Test stimuli appearing as a 3D “ball” than were the healthy participants. Instead, seven PD patients often reported these bidirectional stimuli appeared “flat.” ConclusionsThis study has revealed that some patients with PD have impaired spatio-temporal integration of bidirectional visual motions, but the mechanism accounting for this loss, as well as why only some patients had this deficit, needs further study. When the driver of a moving vehicle fixates upon a stationary target in the surroundings, bidirectional retinal image motions may occur. Failure to perceive 3D structure in such moving scenes can be plausibly suspected to contribute to adverse events such as auto accidents.

Three-Dimensional Kinetic Depth Movement Produced by Single Exposure of Two 2-dimensional Dot Patterns with Brief ISI

Three-Dimensional Kinetic Depth Movement Produced by Single Exposure of Two 2-dimensional Dot Patterns with Brief ISI

Revisiting Motion Parallax as a Source of 3-D Information.

There are many similarities between binocular disparity and motion parallax as sources of information about the structure and layout of 3-D objects and surfaces. The former can be thought of as a transformation that maps one eye's image onto the other while the latter is a transformation that maps the changes in one eye's image over time. There are many empirical similarities in the ways we use the two sources of information but there are also significant differences. A consideration of those differences leads to the conclusion that, rather than seeing motion parallax as a close analogue of binocular stereopsis, motion parallax is better thought of as a special case of the kinetic depth effect in which the depth order of the depicted 3-D object or surface can be disambiguated by vertical perspective information.

The Effectiveness of Vertical Perspective and Pursuit Eye Movements for Disambiguating Motion Parallax Transformations.

In the kinetic depth effect, the direction of the perceived depth and the direction of apparent rotation of a 3-D structure are linked, and typically ambiguous, whereas depth from motion parallax during both observer- and object-movement is stable and unambiguous. Rogers and Rogers demonstrated that the vertical perspective transformations play an important role in disambiguating the direction of the perceived depth in parallax-defined surfaces but more recently Nawrot etal. have proposed that pursuit eye movements provide the crucial disambiguating information. Theoretical considerations suggest that pursuit eye movements could not, in principle, provide the necessary information because 3-D objects as surfaces may rotate during observer- or object-movement. The empirical evidence presented here shows that vertical perspective transformations are sufficient for the unambiguous perception of parallax depth whereas pursuit eye movements are not necessary and may not even be sufficient.

Kinetics of nonstationary migration-accelerated energy transfer in a solid body doped with rare-earth and transition-metal ions

The kinetics of migration-accelerated energy transfer is studied in systems based on a massive crystal and a sample consisting of spherical nanoparticles up to and including four or five orders of magnitude of the kinetic expulsion depth for the case of donor excitation by a short (τpulse < τD) pulse under the action of a multipole mechanism of donor-donor and donor-acceptor energy transfer. The susceptibility of the chosen systems to the implementation of the “jump” mechanism of excitation transfer in them is estimated. It is shown that the nonstationary mechanism of excitation transfer is implemented in the chosen systems based on a sample consisting of nanoparticles.

An Evaluation of Depth Enhancing Perceptual Cues for Vascular Volume Visualization in Neurosurgery

Cerebral vascular images obtained through angiography are used by neurosurgeons for diagnosis, surgical planning, and intraoperative guidance. The intricate branching of the vessels and furcations, however, make the task of understanding the spatial three-dimensional layout of these images challenging. In this paper, we present empirical studies on the effect of different perceptual cues (fog, pseudo-chromadepth, kinetic depth, and depicting edges) both individually and in combination on the depth perception of cerebral vascular volumes and compare these to the cue of stereopsis. Two experiments with novices and one experiment with experts were performed. The results with novices showed that the pseudo-chromadepth and fog cues were stronger cues than that of stereopsis. Furthermore, the addition of the stereopsis cue to the other cues did not improve relative depth perception in cerebral vascular volumes. In contrast to novices, the experts also performed well with the edge cue. In terms of both novice and expert subjects, pseudo-chromadepth and fog allow for the best relative depth perception. By using such cues to improve depth perception of cerebral vasculature, we may improve diagnosis, surgical planning, and intraoperative guidance.

The kinetic depth effect for vision and haptics

The kinetic depth effect for vision and haptics

Disparate time-courses of adaptation and facilitation in multi-stable perception

Far from being “memoryless”, the phenomenal appearance of an ambiguous display depends in complex ways on the recent history of similar perceptions. Given several possible appearances, the continued dominance of one appearance mitigates against its renewed dominance at a later time. This “negative priming” effect is likely caused by neural adaptation. At the same time, continued dominance of one appearance mitigates in favor of its renewed dominance when stimulation resumes after an interruption. This “positive priming” effect may reflect some kind of neural facilitation. We have used a multi-stable, kinetic depth display to disentangle these positive and negative priming effects. We report that negative priming builds up and decays in seconds, whereas positive priming builds up in seconds and decays in minutes. Moreover, unambiguous displays induce negative, but not positive, priming. This difference, together with their disparate time-courses of recovery, render the two effects cleanly dissociable.

A Role of 3-D Surface-from-Motion Cues in Motion-Induced Blindness

Motion-induced blindness (MIB), the illusory disappearance of local targets against a moving mask, has been attributed to both low-level stimulus-based effects and high-level processes, involving selection between local and more global stimulus contexts. Prior work shows that MIB is modulated by binocular disparity-based depth-ordering cues. We assessed whether the depth effect is specific to disparity by studying how monocular 3-D surface from motion affects MIB. Monocular kinetic depth cues were used to create a global 3-D hourglass with concave and convex surfaces. MIB increased for stationary targets on the convex relative to the concave area, extending the role of 3-D cues. Interestingly, this convexity effect was limited to the left visual field--replicating spatial anisotropies in MIB. The data indicate a causal role of general 3-D surface coding in MIB, consistent with MIB being affected by high-level, visual representations.