scholarly journals Perception of light source distance from shading patterns

2016 ◽  
Vol 16 (3) ◽  
pp. 9 ◽  
Author(s):  
Heiko H. Schütt ◽  
Franziska Baier ◽  
Roland W. Fleming
Keyword(s):  
2021 ◽  
Author(s):  
X.Y. Zhu ◽  
S. Inoue ◽  
H. Sato ◽  
Y. Mizokami

Gloss is an essential visual property of objects. It is still controversial how well gloss constancy works under different light distributions. In this paper, we conducted three experiments of different light distributions to investigate whether the stable discrimination and gloss constancy of paper occurred with different glossiness levels at the different light source distances and illuminances. The results suggest instability of paper discrimination and gloss perception when both light source distance and illuminance change. Then we tested two additional conditions. One is setting the distance the same and manipulating the illumination. The other is setting the illuminance constant and manipulating the distance, respectively. We further verify that illuminance and specular reflection can affect material and gloss perception, regardless of the width of the highlight region changed by light source distance.


2008 ◽  
Vol 20 (3) ◽  
Author(s):  
Renny Febrida ◽  
Ellyza Herda ◽  
Andi Soufyan

The use of nano particle composite in posterior region is somehow difficult due to the limited space to place the light source as close as possible to the restorative material. The distance between the light source and restorative material surface leads to decreased light intensity that causing inadequate polymerization. The inadequate polymerization affects the composite diametral tensile strength. Two types of nano particle composite, i.e. FiltekTM Z-350 and Ceram-XTM were tested for their diametral tensile strength, which is affected by the distance of the light source from the composite material surface. Some cylindrical specimens were exposed to light with various distances from the light source, i.e. 0, 1, 2, 3, 4, and 5 mm from the specimen surface. From the six distance variations tested the diametral tensile strength of Filtek Z-350 is 64.09-58.20 MPa with the significant result in 2, 3, 4 and 5 mm distances; and the diametral strenght of Ceram-X is 47.52-42.20 MPa with the significant result in 2, 3, 4 and 5 mm distances. The results of this study show that the increased distance of the light source from the nano particle composite restorative material leads to decreased diametral strength of the two nano particle composites tested.


OSA Continuum ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 720
Author(s):  
Shinichi Inoue ◽  
Norimichi Tsumura

Author(s):  
Michael T. Bucek ◽  
Howard J. Arnott

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.


Author(s):  
Richard G. Sartore

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.


Author(s):  
P.M. Houpt ◽  
A. Draaijer

In confocal microscopy, the object is scanned by the coinciding focal points (confocal) of a point light source and a point detector both focused on a certain plane in the object. Only light coming from the focal point is detected and, even more important, out-of-focus light is rejected.This makes it possible to slice up optically the ‘volume of interest’ in the object by moving it axially while scanning the focused point light source (X-Y) laterally. The successive confocal sections can be stored in a computer and used to reconstruct the object in a 3D image display.The instrument described is able to scan the object laterally with an Ar ion laser (488 nm) at video rates. The image of one confocal section of an object can be displayed within 40 milliseconds (1000 х 1000 pixels). The time to record the total information within the ‘volume of interest’ normally depends on the number of slices needed to cover it, but rarely exceeds a few seconds.


2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.


2003 ◽  
Vol 104 ◽  
pp. 557-561 ◽  
Author(s):  
M. R. Howells ◽  
H. Chapman ◽  
S. Hau-Riege ◽  
H. He ◽  
S. Marchesini ◽  
...  

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.


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