scholarly journals Precedence effect for specular and diffuse reflections

Acta Acustica ◽  
2020 ◽  
Vol 5 ◽  
pp. 1
Author(s):  
Florian Wendt ◽  
Robert Höldrich
Keyword(s):  
Experimental Data ◽  
Total Energy ◽  
Specular Reflection ◽  
Precedence Effect ◽  
Irregular Surface ◽  
Temporal Alignment ◽  
Directional Diffusion ◽  
Specular Reflections ◽  
Temporal Masking ◽  
Listening Experiment

Studies on the precedence effect are typically conducted by presenting two identical sounds simulating direct sound and specular reflection. However, when a sound is reflected from irregular surface, it is redirect into many directions resulting in directional and temporal diffusion. This contribution introduces a simulation of Lambertian diffusing reflections. The perceptual influences of diffusion are studied in a listening experiment; echo thresholds and masked thresholds of specular and diffuse reflections are measured. Results show that diffusion makes the reflections more easily detectable than specular reflections of the same total energy. Indications are found that this mainly due to temporal diffusion, while the directional diffusion has little effect. Accordingly, the modeling of the echo thresholds is achieved by a temporal alignment of the experimental data based on the energy centroid of reflection responses. For the modeling of masked threshold the temporal masking pattern for forward masking is taken into account.

scholarly journals A Method of Predicting the Energy Losses in Vaneless Diffusers of Centrifugal Compressors

1989 ◽  
Author(s):  
Huashu Dou
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Total Energy ◽  
Wall Friction ◽  
Energy Losses ◽  
Flow Conditions ◽  
Centrifugal Compressors ◽  
Flow Losses ◽  
Vaneless Diffusers ◽  
Good Agreement

The flow losses in the veneless diffusers of centrifugal compressors is investigated. It is found that the total energy loss in vaneless diffusers is a function of Bsin2 α0 when inlet flow conditions and radius ratio between inlet and outlet are given. A wall friction coefficient equation is derived and a method of predicting the total energy loss excepting mixing loss is presented. A comparison is made between results obtained from this method and experimental data generated by the author as well as data from the literature. Good agreement is obtained.

scholarly journals X-ray diagnostics of almost transparent Fe plasma of inverted corona target

1999 ◽  
Vol 17 (2) ◽  
pp. 293-298
Author(s):  
A.V. BESSARAB ◽  
S.A. BEL'KOV ◽  
P.D. GASPARYAN ◽  
N.V. ZHIDKOV ◽  
A.V. KUNIN ◽  
...  
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Total Energy ◽  
Resonance Line ◽  
X Ray ◽  
Calculation Results

Measurements of spectral and energy X-ray characteristics of almost transparent Fe plasma produced by laser radiation inside the inverted-corona targets have been made at ISKRA-5 facility. The targets were spherical plastics cavities with 2-mm diameter and 4.6-μm thickness covered from inside with Fe layer 0.25-μm thickness. X-ray spectrum, X-ray total energy, and the energy of a HeαFe resonance line have been measured. Experimental data and calculation results are collated.

Human Factors Assessment of ISO 9241-7, “Requirements for Displays with Reflections”

1998 ◽  
Vol 42 (22) ◽  
pp. 1560-1564
Author(s):  
Gary S. Olacsi ◽  
Joy Kempic ◽  
Robert J. Beaton
Keyword(s):  
Image Quality ◽  
Human Factors ◽  
Specular Reflection ◽  
Visual Display ◽  
Office Work ◽  
Luminance Ratio ◽  
Screen Image ◽  
Specular Reflections ◽  
Degrade Image Quality ◽  
Reading Text

This work evaluated the recently-published ISO 9241-7 “Ergonomic requirements for office work with visual display terminals (VDTs) - Part 7: Requirements for display with reflections” technical standard in terms of perceived image quality judgments for CRT displays. The effects of five illumination conditions and two screen contrast polarities on image quality were assessed for seven CRT/anti-reflection filter configurations. Participants judged the image quality of the displays after reading text passages on the screen. Image quality judgments then were compared to ISO 9241-7 compliance classifications, as well as to two metrics inherent to the standard: screen image luminance ratio and specular reflection luminance ratio. The findings of this work (along with Kempic, Olacsi, and Beaton, 1998) contribute to a human factors justification of ISO 9241-7 and point up several shortcomings in this international standard. In particular, the findings indicate that specular reflections from CRTs degrade image quality more than do diffuse reflections, and, therefore, the importance of specular reflections is understated in the ISO 9241-7 standard.

scholarly journals Can monaural temporal masking explain the ongoing precedence effect?

2018 ◽  
Vol 143 (2) ◽  
pp. EL133-EL139 ◽  
Author(s):  
Richard L. Freyman ◽  
Charlotte Morse-Fortier ◽  
Amanda M. Griffin ◽  
Patrick M. Zurek
Keyword(s):  
Precedence Effect ◽  
Temporal Masking

scholarly journals Light Scattering by Particles with Arbitrary Shape in the Vicinity of the Backward Scattering Direction within Geometrical Optics Approximation

2020 ◽  
Vol 237 ◽  
pp. 08012
Author(s):  
Victor Shishko ◽  
Alexander Konoshonkin ◽  
Natalia Kustova ◽  
Anatoli Borovoi ◽  
Dmitry Timofeev
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Light Scattering ◽  
Arbitrary Shape ◽  
Specular Reflection ◽  
Scattering Problem ◽  
Geometrical Optics ◽  
Optical Characteristics ◽  
Ice Particles ◽  
Scattering Light

The work presents the solution for the light scattering problem by arbitrarily-shaped particles in the vicinity of the backward scattering direction. The solution was obtained within the framework of the geometrical optics approximation. The refractive index was equal to 1.3116. It was shown that the general contribution of scattering light for arbitrarily-shaped particles in the vicinity of the backscattering direction consists of the specular reflection of the particles and two types of non-specular optical beams. It is shown that the optical characteristics of the ice particles with arbitrary shapes correspond to experimental data.

scholarly journals Can monaural temporal masking asymmetry explain the transient and/or ongoing precedence effect?

2013 ◽  
Author(s):  
Richard L. Freyman ◽  
Charlotte Morse-Fortier ◽  
Amanda M. Griffin ◽  
Patrick M. Zurek
Keyword(s):  
Precedence Effect ◽  
Temporal Masking

Can monaural temporal masking asymmetry explain the transient and/or ongoing precedence effect?

2013 ◽  
Vol 133 (5) ◽  
pp. 3514-3514
Author(s):  
Richard L. Freyman ◽  
Charlotte Morse-Fortier ◽  
Amanda M. Griffin ◽  
Patrick M. Zurek
Keyword(s):  
Precedence Effect ◽  
Temporal Masking

scholarly journals SREVAS: Shading Based Surface Refinement under Varying Albedo and Specularity

2020 ◽  
Vol 12 (21) ◽  
pp. 3488
Author(s):  
Zhihua Hu ◽  
Yaolin Hou ◽  
Pengjie Tao ◽  
Jie Shan
Keyword(s):  
Stereo Vision ◽  
Specular Reflection ◽  
Low Cost ◽  
Shape From Shading ◽  
Specular Reflectance ◽  
Specular Reflections ◽  
New Development ◽  
Outdoor Scenes ◽  
Indoor Scenes ◽  
Surface Refinement

Shape-from-shading and stereo vision are two complementary methods to reconstruct 3D surface from images. Stereo vision can reconstruct the overall shape well but is vulnerable in texture-less and non-Lambertian areas where shape-from-shading can recover fine details. This paper presents a novel, generic shading based method to refine the surface generated by multi-view stereo. Different from most of the shading based surface refinement methods, the new development does not assume the ideal Lambertian reflectance, known illumination, or uniform surface albedo. Instead, specular reflectance is taken into account while the illumination can be arbitrary and the albedo can be non-uniform. Surface refinement is achieved by solving an objective function where the imaging process is modeled with spherical harmonics illumination and specular reflectance. Our experiments are carried out using images of indoor scenes with obvious specular reflection and of outdoor scenes with a mixture of Lambertian and specular reflections. Comparing to surfaces created by current multi-view stereo and shape-from-shading methods, the developed method can recover more fine details with lower omission rates (6.11% vs. 24.25%) in the scenes evaluated. The benefit is more apparent when the images are taken with low-cost, off-the-shelf cameras. It is therefore recommended that a general shading model consisting of varying albedo and specularity shall be used in routine surface reconstruction practice.

Human Factors Assessment of ISO 9241-7, “Requirements for Displays with Reflections.”

1998 ◽  
Vol 42 (22) ◽  
pp. 1555-1559
Author(s):  
Joy Kempic ◽  
Gary S. Olacsi ◽  
Robert J. Beaton
Keyword(s):  
Specular Reflection ◽  
Visual Display ◽  
Reading Test ◽  
Office Work ◽  
Luminance Ratio ◽  
Technical Standard ◽  
Large Area ◽  
Specular Reflections ◽  
Degrade Image Quality ◽  
Reading Test Scores

This work evaluated the recently-published ISO 9241-7 “Ergonomic requirements for office work with visual display terminals (VDTs) - Part 7: Requirements for display with reflections” technical standard in terms of the readability of text passages presented on CRT displays. The effects of five illumination conditions and two screen contrast polarities on Tinker Reading Test scores (i.e., reading times and errors) were assessed for seven CRT/anti-reflection filter configurations. The readability scores were compared to ISO 9241-7 compliance classifications obtained for the seven CRT displays, as well as to two contrast metrics underlying the ISO 9241-7 compliance classifications: screen image luminance ratio and specular reflection luminance ratio. The findings show that only the specular reflection luminance ratio for large-area, negative polarity correlated with reading times. The present findings, along with those in a companion work (Olacsi, Kempic, and Beaton, 1998), contribute to the understanding of CRT viewability in glare environments and point out some shortcomings of ISO 9241-7. In particular, the findings indicate that specular reflections from CRTs degrade image quality more than do diffuse reflections, and, therefore, the importance of specular reflections is underemphasized in the ISO 9241-7 standard.

Energy loss of protons passing through hydrogen

1955 ◽  
Vol 232 (1190) ◽  
pp. 423-434 ◽  
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Total Energy ◽  
Detailed Analysis ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Heavy Particle ◽  
Stopping Power ◽  
Particle Collisions ◽  
Hydrogen Atoms

The cross-sections of processes involving protons and hydrogen atoms calculated by Bates, Dalgarno and Griffing using the Bom approximation are employed to make a detailed analysis of the contributions of excitation, ionization and capture to the stopping power of a gas of atomic hydrogen for a beam consisting initially of protons. A range of beam energies from 10 keV to 3 MeV is covered. The computed total energy loss is compared with experimental data and the accuracy of the Bom approximation for heavy particle collisions is discussed.

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