scholarly journals Differential processing of binocular and monocular gloss cues in human visual cortex

2016 ◽  
Vol 115 (6) ◽  
pp. 2779-2790 ◽  
Author(s):  
Hua-Chun Sun ◽  
Massimiliano Di Luca ◽  
Hiroshi Ban ◽  
Alexander Muryy ◽  
Roland W. Fleming ◽  
...  
Keyword(s):  
Material Properties ◽  
Visual Cues ◽  
Surface Material ◽  
Multivoxel Pattern Analysis ◽  
Differential Processing ◽  
Material Appearance ◽  
Visual Areas ◽  
High Level ◽  
Ventral Area ◽  
Surface Gloss

The visual impression of an object's surface reflectance (“gloss”) relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues.

scholarly journals Material category determined by specular reflection structure mediates the processing of image features for perceived gloss

2020 ◽  
Author(s):  
Alexandra C. Schmid ◽  
Pascal Barla ◽  
Katja Doerschner
Keyword(s):  
Material Properties ◽  
Specular Reflection ◽  
Visual Image ◽  
Feature Space ◽  
Image Features ◽  
Material Recognition ◽  
Material Appearance ◽  
Precise Relationship ◽  
High Level ◽  
Surface Gloss

ABSTRACTThere is a growing body of work investigating the visual perception of material properties like gloss, yet practically nothing is known about how the brain recognises different material classes like plastic, pearl, satin, and steel, nor the precise relationship between material properties like gloss and perceived material class. We report a series of experiments that show that parametrically changing reflectance parameters leads to qualitative changes in material appearance beyond those expected by the reflectance function used. We measure visual (image) features that predict these changes in appearance, and causally manipulate these features to confirm their role in perceptual categorisation. Furthermore, our results suggest that the same visual features underlie both material recognition and surface gloss perception. However, the predictiveness of each feature to perceived gloss changes with material category, suggesting that the pockets of feature space occupied by different material classes affect the processing of those very features when estimating surface glossiness. Our results do not support a traditional feedforward view that assumes that material perception proceeds from low-level image measurements, to mid-level estimates of surface properties, to high-level material classes, nor the idea that material properties like gloss and material class are simultaneously “read out” from visual gloss features. Instead, we suggest that the perception and neural processing of material properties like surface gloss should be considered in the context of material recognition.

scholarly journals Expectations affect the perception of material properties

2019 ◽  
Author(s):  
Lorilei M. Alley ◽  
Alexandra C. Schmid ◽  
Katja Doerschner
Keyword(s):  
Optical Properties ◽  
Visual Perception ◽  
Material Properties ◽  
Time Data ◽  
Material Appearance ◽  
Typical Material ◽  
Material Behaviors ◽  
Set Up ◽  
High Level ◽  
Cue Conflict

ABSTRACTMany objects that we encounter have ‘typical’ material qualities: spoons are hard, pillows are soft, and jell-O dessert is wobbly. Over a lifetime of experiences, strong associations between an object and its typical material properties may be formed, and these associations not only include how glossy, rough or pink an object is, but also how it behaves under force: we expect knocked over vases to shatter, popped bike tires to deflate, and gooey grilled cheese to hang between two slices of bread when pulled apart. Here we ask how such rich visual priors affect the visual perception of material qualities and present a particularly striking example of expectation violation. In a cue conflict design, we pair computer-rendered familiar objects with surprising material behaviors (a linen curtain shattering, a porcelain teacup wrinkling, etc.) and find that material qualities are not solely estimated from the object’s kinematics (i.e. its physical (atypical) motion while shattering, wrinkling, wobbling etc.); rather, material appearance is sometimes “pulled” towards the “native” motion, shape, and optical properties that are associated with this object. Our results, in addition to patterns we find in response time data, suggest that visual priors about materials can set up high-level expectations about complex future states of an object and show how these priors modulate material appearance.

Clutter Modulates the Representation of Target Objects in the Human Occipitotemporal Cortex

2014 ◽  
Vol 26 (3) ◽  
pp. 490-500 ◽  
Author(s):  
Yaara Erez ◽  
Galit Yovel
Keyword(s):  
Target Identification ◽  
Neural Representation ◽  
Multivoxel Pattern Analysis ◽  
Face Area ◽  
Visual Areas ◽  
Occipitotemporal Cortex ◽  
Object Area ◽  
High Level ◽  
Goal Directed Behavior ◽  
Parahippocampal Place Area

Target objects required for goal-directed behavior are typically embedded within multiple irrelevant objects that may interfere with their encoding. Most neuroimaging studies of high-level visual cortex have examined the representation of isolated objects, and therefore, little is known about how surrounding objects influence the neural representation of target objects. To investigate the effect of different types of clutter on the distributed responses to target objects in high-level visual areas, we used fMRI and manipulated the type of clutter. Specifically, target objects (i.e., a face and a house) were presented either in isolation, in the presence of a homogeneous (identical objects from another category) clutter (“pop-out” display), or in the presence of a heterogeneous (different objects) clutter, while participants performed a target identification task. Using multivoxel pattern analysis (MVPA) we found that in the posterior fusiform object area a heterogeneous but not homogeneous clutter interfered with decoding of the target objects. Furthermore, multivoxel patterns evoked by isolated objects were more similar to multivoxel patterns evoked by homogenous compared with heterogeneous clutter in the lateral occipital and posterior fusiform object areas. Interestingly, there was no effect of clutter on the neural representation of the target objects in their category-selective areas, such as the fusiform face area and the parahippocampal place area. Our findings show that the variation among irrelevant surrounding objects influences the neural representation of target objects in the object general area, but not in object category-selective cortex, where the representation of target objects is invariant to their surroundings.

FEMLIB: An Object-Oriented Framework for Optimization and Simulation

1995 ◽  
Author(s):  
Michael M. Tiller ◽  
Jonathan A. Dantzig
Keyword(s):  
Material Properties ◽  
Object Oriented ◽  
The Finite Element Method ◽  
Simulation And Optimization ◽  
Gradient Based ◽  
Level Problem ◽  
Simulation Results ◽  
Optimization And Simulation ◽  
High Level ◽  
Simulation Parameters

Abstract In this paper we discuss the design of an object-oriented framework for simulation and optimization. Although oriented around high-level problem solving, the framework defines several classes of problems and includes concrete implementations of common algorithms for solving these problems. Simulations are run by combining these algorithms, as needed, for a particular problem. Included in this framework is the capability to compute the sensitivity of simulation results to the different simulation parameters (e.g. material properties, boundary conditions, etc). This sensitivity information is valuable in performing optimization because it allows the use of gradient-based optimization algorithms. Also included in the system are many useful abstractions and implementations related to the finite element method.

scholarly journals Field (In)dependence Flexibility Following a Virtual Immersion Is Associated With Cybersickness and Sense of Presence

2021 ◽  
Vol 2 ◽  
Author(s):  
A. Maneuvrier ◽  
L. M. Decker ◽  
P. Renaud ◽  
G. Ceyte ◽  
H. Ceyte
Keyword(s):  
Visual Cues ◽  
Subjective Experience ◽  
A Posteriori ◽  
Future Studies ◽  
Sense Of Presence ◽  
Before And After ◽  
High Level ◽  
Shed Light ◽  
Rod And Frame Test ◽  
Rod And Frame

Field dependence–independence (FDI) is a psychological construct determining an individual’s approach of the perception–cognition coupling. In virtual reality (VR) context, several studies suggest that an individual’s perceptive style is susceptible to shift toward a more FI mode through down-weighting of conflicting visual cues. The present study proposes to investigate the potential flexible nature of FDI following a virtual immersion and to assess if this flexibility might be associated with the subjective experience of VR. 86 participants explored a real-world–like virtual environment for approximately 10 min. FDI levels were measured before and after the VR exposure using the rod-and-frame test. Their subjective experience of VR was measured a posteriori (cybersickness and sense of presence) and used in order to build two experimental groups via a cluster analysis. The results showed that only participants with a poor subjective experience of VR (i.e., a low level of sense of presence associated with a high level of cybersickness) significantly shifted to a more FI mode, which is discussed as a sensory re-weighting mechanism. Pragmatical applications are discussed, and future studies are outlined, based on the conclusion that FDI might be more flexible than we thought, which could shed light on the psychophysiology of VR.

Assessment of delamination location in composite laminates based on a chaotic oscillator method

2021 ◽  
Vol 263 (2) ◽  
pp. 4709-4716
Author(s):  
Xuan Li ◽  
Dunant Halim ◽  
Xiaoling Liu
Keyword(s):  
Material Properties ◽  
Composite Laminates ◽  
Damage Index ◽  
Vibration Signal ◽  
Harmonic Excitation ◽  
Vibration Measurement ◽  
Chaotic Oscillator ◽  
Signal Characteristics ◽  
High Level ◽  
Delamination Damage

The work aims to study the assessment of delamination location in composite laminates using vibration measurement with a chaotic oscillator method. Delamination is a type of damage that commonly occurs in composite laminates, which can cause a severe degradation of their material properties. The traditional vibration-based methods can encounter difficulties in detecting and locating these delamination-type damages especially when the size of delamination is relatively small and there is a significant level of noise in its vibration measurement. With this particular consideration, a vibration-based method using a non-linear chaotic oscillator was used in this study due to its sensitivity to the change in vibration signal characteristics. A numerical model of composite laminates with delamination damage under harmonic excitation was developed and the vibration signal obtained from composite laminates was processed using the chaotic oscillator method. A feature named Lyapunov Exponent (LE) was used as a delamination damage index to describe the characteristics of the chaotic oscillator for cases with delamination at varying structural locations. The effects of delamination locations on the developed damage index were analyzed in this work. The results showed that there was a strong correlation between the delamination location and the LE feature, even for the case with a relatively high level of measurement noise. The results demonstrated the effectiveness of the method to identify delamination in composite laminates, which has also the potential to be used to detect other types of damages.

scholarly journals Use of head camera-cued recall and debrief to externalise expertise: a systematic review of literature from multiple fields of practice

2018 ◽  
Vol 5 (3) ◽  
pp. 121-129
Author(s):  
Vivienne Isabella Blackhall ◽  
Kenneth Grant Walker ◽  
Iya Whiteley ◽  
Philip Wilson
Keyword(s):  
Decision Making ◽  
Visual Cues ◽  
Video Recording ◽  
Cognitive Activity ◽  
Cued Recall ◽  
Point Of View ◽  
Current Evidence ◽  
Training Tool ◽  
Registration Number ◽  
High Level

BackgroundThe study of decision making in complex naturalistic environments poses several challenges. In response to these, video-stimulated cued-recall-debrief was developed. It involves an individual wearing a head-mounted camera which records a task from their point of view. Afterwards, footage captured is reviewed along with a facilitated debrief to help externalise cognitive processes. In theory, motion, audio and visual cues generate a high level of experiential immersion which helps the expert to articulate previously hidden thoughts and actions.ObjectiveTo examine the current evidence for video-stimulated cued-recall-debrief as a means of explicating expert thoughts and feelings in complex tasks in a range of environments.Study selectionMEDLINE, EMBASE, Education Resources Information Center, SPORTDiscus, PsycINFO and Google Scholar were searched for articles containing the key terms ‘cued-recall (debrief)’, ‘decision making’, ‘skills’ and ‘video recording’. Studies were included if they examined the following outcomes: (1) feasibility, (2) extent of experiential immersion, (3) ability to generate unique insight into decision-making processes and (4) current applications. 1831 articles were identified initially, and 9 studies were included in the final review.FindingsVideo-stimulated cued-recall-debrief is associated with a high level of experiential immersion and generates between two and four times the number of recollections compared with free recall. It can be used to build models of cognitive activity and to characterise the way in which more and less skilled individuals tend to think and feel.ConclusionsThe technique could be used to explicate expertise within medicine: these insights into performance could be used as a training tool for other practitioners.Trial registration numberCRD42017057484.

scholarly journals Dense, Strong, and Precise Silicon Nitride-Based Ceramic Parts by Lithography-Based Ceramic Manufacturing

2020 ◽  
Vol 10 (3) ◽  
pp. 996 ◽  
Author(s):  
Altan Alpay Altun ◽  
Thomas Prochaska ◽  
Thomas Konegger ◽  
Martin Schwentenwein
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
Light Scattering ◽  
Silicon Nitride ◽  
Material Properties ◽  
Refractive Indices ◽  
High Relative Density ◽  
Ceramic Manufacturing ◽  
High Level ◽  
First Time

Due to the high level of light absorption and light scattering of dark colored powders connected with the high refractive indices of ceramic particles, the majority of ceramics studied via stereolithography (SLA) have been light in color, including ceramics such as alumina, zirconia and tricalcium phosphate. This article focuses on a lithography-based ceramic manufacturing (LCM) method for β-SiAlON ceramics that are derived from silicon nitride and have excellent material properties for high temperature applications. This study demonstrates the general feasibility of manufacturing of silicon nitride-based ceramic parts by LCM for the first time and combines the advantages of SLA, such as the achievable complexity and low surface roughness (Ra = 0.50 µm), with the typical properties of conventionally manufactured silicon nitride-based ceramics, such as high relative density (99.8%), biaxial strength (σf = 764 MPa), and hardness (HV10 = 1500).

scholarly journals A data‐driven approach to stimulus selection reveals an image‐based representation of objects in high‐level visual areas

2019 ◽  
Vol 40 (16) ◽  
pp. 4716-4731 ◽  
Author(s):  
David D. Coggan ◽  
Afrodite Giannakopoulou ◽  
Sanah Ali ◽  
Burcu Goz ◽  
David M. Watson ◽  
...  
Keyword(s):  
Data Driven ◽  
Stimulus Selection ◽  
Visual Areas ◽  
Data Driven Approach ◽  
High Level
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