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Article ; Online: Lightness Perception in Complex Scenes.

Murray, Richard F

2021 Volume 7, Page(s) 417–436

Abstract: Lightness perception is the perception of achromatic surface colors: black, white, and shades of grey. Lightness has long been a central research topic in experimental psychology, as perceiving surface color is an important visual task but also a ... ...

Abstract	Lightness perception is the perception of achromatic surface colors: black, white, and shades of grey. Lightness has long been a central research topic in experimental psychology, as perceiving surface color is an important visual task but also a difficult one due to the deep ambiguity of retinal images. In this article, I review psychophysical work on lightness perception in complex scenes over the past 20 years, with an emphasis on work that supports the development of computational models. I discuss Bayesian models, equivalent illumination models, multidimensional scaling, anchoring theory, spatial filtering models, natural scene statistics, and related work in computer vision. I review open topics in lightness perception that seem ready for progress, including the relationship between lightness and brightness, and developing more sophisticated computational models of lightness in complex scenes.
MeSH term(s)	Bayes Theorem ; Contrast Sensitivity ; Lighting ; Photic Stimulation/methods
Language	English
Publishing date	2021-07-01
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Review
ZDB-ID	2805730-2
ISSN	2374-4650 ; 2374-4642
ISSN (online)	2374-4650
ISSN	2374-4642
DOI	10.1146/annurev-vision-093019-115159
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: A model of lightness perception guided by probabilistic assumptions about lighting and reflectance.

Murray, Richard F

Journal of vision

2020 Volume 20, Issue 7, Page(s) 28

Abstract: Lightness perception is the ability to perceive black, white, and gray surface colors in a wide range of lighting conditions and contexts. This ability is fundamental for any biological or artificial visual system, but it poses a difficult computational ... ...

Abstract	Lightness perception is the ability to perceive black, white, and gray surface colors in a wide range of lighting conditions and contexts. This ability is fundamental for any biological or artificial visual system, but it poses a difficult computational problem, and how the human visual system computes lightness is not well understood. Here I show that several key phenomena in lightness perception can be explained by a probabilistic graphical model that makes a few simple assumptions about local patterns of lighting and reflectance, and infers globally optimal interpretations of stimulus images. Like human observers, the model exhibits partial lightness constancy, codetermination, contrast, glow, and articulation effects. It also arrives at human-like interpretations of strong lightness illusions that have challenged previous models. The model's assumptions are reasonable and generic, including, for example, that lighting intensity spans a much wider range than surface reflectance and that shadow boundaries tend to be straighter than reflectance edges. Thus, a probabilistic model based on simple assumptions about lighting and reflectance gives a good computational account of lightness perception over a wide range of conditions. This work also shows how graphical models can be extended to develop more powerful models of constancy that incorporate features such color and depth.
MeSH term(s)	Computer Simulation ; Contrast Sensitivity/physiology ; Humans ; Light ; Probability ; Visual Perception/physiology
Language	English
Publishing date	2020-07-26
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2106064-2
ISSN	1534-7362 ; 1534-7362
ISSN (online)	1534-7362
ISSN	1534-7362
DOI	10.1167/jov.20.7.28
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Article ; Online: Luminance calibration of virtual reality displays in Unity.

Murray, Richard F / Patel, Khushbu Y / Wiedenmann, Emma S

Journal of vision

2022 Volume 22, Issue 13, Page(s) 1

Abstract: Virtual reality (VR) displays are an increasingly popular medium for experiments on visual perception. This presents the challenge of showing precisely controlled stimuli on devices that were not primarily designed for research. Here we describe methods ... ...

Abstract	Virtual reality (VR) displays are an increasingly popular medium for experiments on visual perception. This presents the challenge of showing precisely controlled stimuli on devices that were not primarily designed for research. Here we describe methods for controlling stimulus luminance in VR experiments created in Unity using the Built-in Render Pipeline. We discuss the Gamma/Linear setting, measuring luminance in a VR headset, and using color grading in Unity's Post-Processing Stack to make stimulus luminance proportional to achromatic RGB value. We provide MATLAB code that uses luminance measurements from a VR headset to generate the lookup table that Unity requires for linearizing luminance. We emphasize that when creating experiments in this complex environment, it is important to experiment with the rendering process to confirm that stimuli are displayed as expected. We show results of several such tests and provide code as a starting point for readers who wish to run further tests related to their own research.
MeSH term(s)	Humans ; Calibration ; Virtual Reality ; Visual Perception
Language	English
Publishing date	2022-12-01
Publishing country	United States
Document type	Journal Article
ZDB-ID	2106064-2
ISSN	1534-7362 ; 1534-7362
ISSN (online)	1534-7362
ISSN	1534-7362
DOI	10.1167/jov.22.13.1
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Article ; Online: Lightness constancy in reality, in virtual reality, and on flat-panel displays.

Patel, Khushbu Y / Wilcox, Laurie M / Maloney, Laurence T / Ehinger, Krista A / Patel, Jaykishan Y / Wiedenmann, Emma / Murray, Richard F

Behavior research methods

2024

Abstract: Virtual reality (VR) displays are being used in an increasingly wide range of applications. However, previous work shows that viewers often perceive scene properties very differently in real and virtual environments and so realistic perception of virtual ...

Abstract	Virtual reality (VR) displays are being used in an increasingly wide range of applications. However, previous work shows that viewers often perceive scene properties very differently in real and virtual environments and so realistic perception of virtual stimuli should always be a carefully tested conclusion, not an assumption. One important property for realistic scene perception is surface color. To evaluate how well virtual platforms support realistic perception of achromatic surface color, we assessed lightness constancy in a physical apparatus with real lights and surfaces, in a commercial VR headset, and on a traditional flat-panel display. We found that lightness constancy was good in all three environments, though significantly better in the real environment than on the flat-panel display. We also found that variability across observers was significantly greater in VR and on the flat-panel display than in the physical environment. We conclude that these discrepancies should be taken into account in applications where realistic perception is critical but also that in many cases VR can be used as a flexible alternative to flat-panel displays and a reasonable proxy for real environments.
Language	English
Publishing date	2024-03-05
Publishing country	United States
Document type	Journal Article
ZDB-ID	231560-9
ISSN	1554-3528 ; 0743-3808 ; 1554-351X
ISSN (online)	1554-3528
ISSN	0743-3808 ; 1554-351X
DOI	10.3758/s13428-024-02352-0
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Z 76/512: Show issues

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Book: Monitoring rocky shores

Murray, Steven N. / Ambrose, Richard F. / Dethier, Megan N.

2006

Author's details	Steven N. Murray ; Richard F. Ambrose ; Megan N. Dethier
Keywords	Intertidal ecology/Research/Methodology ; Environmental monitoring/Methodology
Subject code	577.699
Language	English
Size	XVI, 220 S. : Ill., graph. Darst., Kt., 23cm
Publisher	Univ. of California Press
Publishing place	Berkeley, Calif. u.a.
Publishing country	United States
Document type	Book
Note	Includes bibliographical references
HBZ-ID	HT014564389
ISBN	0-520-24728-0 ; 978-0-520-24728-4
Database	Catalogue ZB MED Nutrition, Environment, Agriculture

In stock of ZB MED Bonn / Germany

Shelf mark	Loan status	Location
068/769	available for loan (reading room)	Freihandmagazin (U1)

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Article ; Online: Classification images in a very general decision model.

Murray, Richard F

Vision research

2016 Volume 123, Page(s) 26–32

Abstract: Most of the theory supporting our understanding of classification images relies on standard signal detection models and the use of normally distributed stimulus noise. Here I show that the most common methods of calculating classification images by ... ...

Abstract	Most of the theory supporting our understanding of classification images relies on standard signal detection models and the use of normally distributed stimulus noise. Here I show that the most common methods of calculating classification images by averaging stimulus noise samples within stimulus-response classes of trials are much more general than has previously been demonstrated, and that they give unbiased estimates of an observer's template for a wide range of decision rules and non-Gaussian stimulus noise distributions. These results are similar to findings on reverse correlation and related methods in the neurophysiology literature, but here I formulate them in terms that are tailored to signal detection analyses of visual tasks, in order to make them more accessible and useful to visual psychophysicists. I examine 2AFC and yes-no designs. These findings make it possible to use and interpret classification images in tasks where observers' decision strategies may not conform to classic signal detection models such as the difference rule, and in tasks where the stimulus noise is non-Gaussian.
MeSH term(s)	Contrast Sensitivity ; Decision Making ; Humans ; Models, Theoretical ; Normal Distribution ; Pattern Recognition, Visual ; Signal Detection, Psychological ; Visual Perception/physiology
Language	English
Publishing date	2016-06
Publishing country	England
Document type	Journal Article
ZDB-ID	200427-6
ISSN	1878-5646 ; 0042-6989
ISSN (online)	1878-5646
ISSN	0042-6989
DOI	10.1016/j.visres.2016.04.003
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Zs.A 521: Show issues

Location:
Je nach Verfügbarkeit (siehe Angabe bei Bestand)
bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
Jg. 1995 - 2021: Lesesall (1.OG)
ab Jg. 2022: Lesesaal (EG)

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Article: Aggregate-prone brain regions in Parkinson's disease are rich in unique N-terminus α-synuclein conformers with high proteolysis susceptibility.

Wiseman, James A / Murray, Helen C / Faull, Richard L M F / Dragunow, Michael / Turner, Clinton P / Dieriks, Birger Victor / Curtis, Maurice A

NPJ Parkinson's disease

2024 Volume 10, Issue 1, Page(s) 1

Abstract: In Parkinson's disease (PD), and other α-synucleinopathies, α-synuclein (α-Syn) aggregates form a myriad of conformational and truncational variants. Most antibodies used to detect and quantify α-Syn in the human brain target epitopes within the C- ... ...

Abstract	In Parkinson's disease (PD), and other α-synucleinopathies, α-synuclein (α-Syn) aggregates form a myriad of conformational and truncational variants. Most antibodies used to detect and quantify α-Syn in the human brain target epitopes within the C-terminus (residues 96-140) of the 140 amino acid protein and may fail to capture the diversity of α-Syn variants present in PD. We sought to investigate the heterogeneity of α-Syn conformations and aggregation states in the PD human brain by labelling with multiple antibodies that detect epitopes along the entire length of α-Syn. We used multiplex immunohistochemistry to simultaneously immunolabel tissue sections with antibodies mapping the three structural domains of α-Syn. Discrete epitope-specific immunoreactivities were visualised and quantified in the olfactory bulb, medulla, substantia nigra, hippocampus, entorhinal cortex, middle temporal gyrus, and middle frontal gyrus of ten PD cases, and the middle temporal gyrus of 23 PD, and 24 neurologically normal cases. Distinct Lewy neurite and Lewy body aggregate morphologies were detected across all interrogated regions/cases. Lewy neurites were the most prominent in the olfactory bulb and hippocampus, while the substantia nigra, medulla and cortical regions showed a mixture of Lewy neurites and Lewy bodies. Importantly, unique N-terminus immunoreactivity revealed previously uncharacterised populations of (1) perinuclear, (2) glial (microglial and astrocytic), and (3) neuronal lysosomal α-Syn aggregates. These epitope-specific N-terminus immunoreactive aggregate populations were susceptible to proteolysis via time-dependent proteinase K digestion, suggesting a less stable oligomeric aggregation state. Our identification of unique N-terminus immunoreactive α-Syn aggregates adds to the emerging paradigm that α-Syn pathology is more abundant and complex in human brains with PD than previously realised. Our findings highlight that labelling multiple regions of the α-Syn protein is necessary to investigate the full spectrum of α-Syn pathology and prompt further investigation into the functional role of these N-terminus polymorphs.
Language	English
Publishing date	2024-01-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	2819218-7
ISSN	2373-8057
ISSN	2373-8057
DOI	10.1038/s41531-023-00614-w
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Article ; Online: Number Adaptation Can Be Dissociated From Density Adaptation.

DeSimone, Kevin / Kim, Minjung / Murray, Richard F

Psychological science

2020 Volume 31, Issue 11, Page(s) 1470–1474

Abstract: Rapidly judging the number of objects in a scene is an important perceptual ability. Recent debates have centered on whether number perception is accomplished by dedicated mechanisms and, in particular, on whether number-adaptation aftereffects reflect ... ...

Abstract	Rapidly judging the number of objects in a scene is an important perceptual ability. Recent debates have centered on whether number perception is accomplished by dedicated mechanisms and, in particular, on whether number-adaptation aftereffects reflect adaptation of number per se or adaptation of related stimulus properties, such as density. Here, we report an adaptation experiment (
MeSH term(s)	Adaptation, Physiological ; Figural Aftereffect ; Humans ; Photic Stimulation ; Psychophysics
Language	English
Publishing date	2020-10-20
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2022256-7
ISSN	1467-9280 ; 0956-7976
ISSN (online)	1467-9280
ISSN	0956-7976
DOI	10.1177/0956797620956986
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Article ; Online: Toward Automatic Inference of Glycan Linkages Using MS

Ni, Xinyi / Murray, Nathan B / Archer-Hartmann, Stephanie / Pepi, Lauren E / Helm, Richard F / Azadi, Parastoo / Hong, Pengyu

Journal of the American Society for Mass Spectrometry

2023 Volume 34, Issue 10, Page(s) 2127–2135

Abstract: Glycosidic linkages in oligosaccharides play essential roles in determining their chemical properties and biological activities. ... ...

Abstract	Glycosidic linkages in oligosaccharides play essential roles in determining their chemical properties and biological activities. MS
MeSH term(s)	N-Acetylneuraminic Acid/chemistry ; Polysaccharides/analysis ; Mass Spectrometry/methods ; Oligosaccharides/chemistry ; Chromatography, Liquid
Chemical Substances	N-Acetylneuraminic Acid (GZP2782OP0) ; Polysaccharides ; Oligosaccharides
Language	English
Publishing date	2023-08-24
Publishing country	United States
Document type	Journal Article
ZDB-ID	1073671-2
ISSN	1879-1123 ; 1044-0305
ISSN (online)	1879-1123
ISSN	1044-0305
DOI	10.1021/jasms.3c00132
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Zs.A 4618: Show issues			Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (2.OG) ab Jg. 2022: Lesesaal (EG)
Zs.MO 241: Show issues

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Article ; Online: Postoperative Infection and Revision Surgery Rates in Foot and Ankle Surgery Without Routine Prescription of Prophylactic Antibiotics.

Huang, Neal / Miles, Daniel T / Read, Connor R / White, Charles C / Murray, Richard D / Wilson, Andrew W / Doty, Jesse F

Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews

2023 Volume 7, Issue 3

Abstract: Introduction: Surgical site infections (SSIs) are associated with patient morbidity and increased healthcare costs. Limited literature in foot and ankle surgery provides guidance about routine administration of postoperative antibiotic prophylaxis. The ... ...

Abstract	Introduction: Surgical site infections (SSIs) are associated with patient morbidity and increased healthcare costs. Limited literature in foot and ankle surgery provides guidance about routine administration of postoperative antibiotic prophylaxis. The purpose of this study was to examine the incidence and revision surgery rates of SSI in outpatient foot and ankle surgeries in patients not receiving oral postoperative antibiotic prophylaxis. Methods: A retrospective review of all outpatient surgeries (n = 1517) conducted by a single surgeon in a tertiary referral academic center was conducted through electronic medical records. Incidence of SSI, revision surgery rate, and associated risk factors were determined. The median follow-up was 6 months. Results: Postoperative infection occurred in 2.9% (n = 44) of the surgeries conducted, with 0.9% of patients (n = 14) requiring return to the operating room. Thirty patients (2.0%) were diagnosed with simple superficial infections, which resolved with local wound care and oral antibiotics. Diabetes (adjusted odds ratio, 2.09; 95% confidence interval, 1.00 to 4.38; P = 0.049) and increasing age (adjusted odds ratio, 1.02; 95% confidence interval, 1.00 to 1.04; P = 0.016) were significantly associated with postoperative infection. Discussion: This study demonstrated low postoperative infection and revision surgery rates without the routine prescription of prophylactic postoperative antibiotics. Increasing age and diabetes are signficant risk factors for developing a postoperative infection.
MeSH term(s)	Humans ; Ankle/surgery ; Reoperation ; Anti-Bacterial Agents/therapeutic use ; Antibiotic Prophylaxis/adverse effects ; Communicable Diseases/drug therapy ; Communicable Diseases/etiology ; Communicable Diseases/surgery ; Prescriptions
Chemical Substances	Anti-Bacterial Agents
Language	English
Publishing date	2023-03-08
Publishing country	United States
Document type	Journal Article
ZDB-ID	2898328-2
ISSN	2474-7661 ; 1067-151X
ISSN (online)	2474-7661
ISSN	1067-151X
DOI	10.5435/JAAOSGlobal-D-23-00015
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