scholarly journals Method for the numerical evaluation of the color rendering quality of matrix photodetectors

2021 ◽  
pp. 39-44
Author(s):  
Oleksandr Kupko ◽  
Olena Liashenko ◽  
Pavel Neyezhmakov ◽  
Yevhen Tymofeiev ◽  
Eduard Diumin ◽  
...  
Keyword(s):  
Color Image ◽  
Spectral Characteristics ◽  
Light Sources ◽  
Color Coordinates ◽  
Visual Impression ◽  
Digital Format ◽  
The Difference ◽  
Angular Coordinates ◽  
Color Rendering

To objectively evaluate the color image of an architectural object when changing its spectral quality and luminance in lighting, it is necessary to ensure its accurate fixation. The measurement of the color coordinates of an object provides the fully capture of its appearance, but this does not allow to get an adequate evaluation of the visual impression without visualizing the lighting scene. This requires a thorough procedure of reproducing the same color coordinates for each point of the image and the object with the same angular coordinates. In this work, an attempt is made to develop a numerical criterion for evaluating the quality of color rendering of the camera as a fixer of color visual impression of the selected scene. The development of a numerical detailed method for evaluation of the quality of color rendering of cameras will allow capturing more reliably such a subjective concept as the correspondence of the visual impression of the real scene and the image file of this scene. The digital format, which contains information about the object, avoids the problems associated with aging of the image. The proposed method of developing ways to numerically evaluate color distortion in photography is considered on the example of digital cameras Nikon D300s, Sony DSC-H5. The described approach for the case of known spectral characteristics allows to unambiguously link the calculated reaction of the camera with the chromaticity coordinates of spectrally pure colors. Modern methods of evaluating the quality of light sources (IES TM-30-15) allow evaluation of the direction of the shift. The proposed indicator – graph E (λi) numerically characterizes the difference between the reaction of the camera and the reaction of the human eye and does not give an idea in which direction there is a difference, conditionally red or blue image compared to the natural scene, but is the simplest and most understandable to the untrained user. It is shown that with an accuracy of measuring spectral characteristics of 1% for the considered example with Nikon D300s, this indicator at different wavelengths is calculated with an uncertainty of not more than 0.002.

scholarly journals Enhancement of Satellite Imagesusing Image Sharpening Technique

2019 ◽  
Vol 8 (6S2) ◽  
pp. 351-354
Keyword(s):  
Image Processing ◽  
Color Image ◽  
Histogram Equalization ◽  
Grayscale Image ◽  
Original Image ◽  
High Quality ◽  
Wide Range ◽  
Equalization Technique ◽  
The Difference

In many image processing applications, a wide range of image enhancement techniques are being proposed. Many of these techniques demanda lot of critical and advance steps, but the resultingimage perception is not satisfactory. This paper proposes a novel sharpening method which is being experimented with additional steps. In the first step, the color image is transformed into grayscale image, then edge detection process is applied using Laplacian technique. Then deduct this image from the original image. The resulting image is as expected; After performing the enhancement process,the high quality of the image can be indicated using the Tenengrad criterion. The resulting image manifested the difference in certain areas, the dimension and the depth as well. Histogram equalization technique can also be applied to change the images color.

scholarly journals Luminous and Melanopic Efficiency Performance of Phosphor-Converted LEDs with Tunable Spectral Characteristics

2020 ◽  
Vol 10 (18) ◽  
pp. 6198
Author(s):  
Peiyu Wu ◽  
Jiaqi Ju ◽  
Qi Yao
Keyword(s):  
Intensity Distribution ◽  
Emission Intensity ◽  
Spectral Characteristics ◽  
Spectral Composition ◽  
Light Sources ◽  
Peak Wavelength ◽  
Efficiency Performance ◽  
Circadian Effect ◽  
Color Rendering ◽  
Blue Intensity

In this work, we investigated the luminous and melanopic efficiency of the radiation (LER/MER) performances of phosphor-converted LEDs (PC LEDs) with tunable spectral characteristics, namely peak wavelength, full width at half maximum (FWHM), and emission intensity. We constructed theoretical PC LED spectra based on the characteristics extracted from the database of IES TM-30-15, analyzed the relations between LER/MER and different spectral characteristics, and proposed spectral composition strategies at various correlated color temperatures (CCTs). Results showed that both MER and LER are linear with the FWHM of phosphor within the peak wavelength range in practical use, but the change in values by tuning emission intensity varies with spectral compositions. Hence, different spectral characteristics should be considered comprehensively. We further explored the trade-off between luminous and melanopic efficiency. Lowering the FWHM of phosphor and the intensity distribution of the blue LED can obtain higher LER and low circadian effect at lower CCT. As CCT increases, considering color rendering and the increase in the blue intensity distribution, besides reducing FWHM, tuning the peak wavelength close to the peak wavelength of V(λ) helps to reduce the circadian effect. These investigations provide optimization strategies for ideal melanopic and luminous performance of PC LED light sources.

DOZ047.116: Reducing complications for tracheostomy patients

2019 ◽  
Vol 32 (Supplement_1) ◽  
Author(s):  
T Valika ◽  
D M Thompson ◽  
J Ida
Keyword(s):  
Wound Care ◽  
Healthcare Providers ◽  
Retrospective Chart Review ◽  
Emergency Situations ◽  
Wound Breakdown ◽  
Digital Format ◽  
Time Period ◽  
Postoperative Time ◽  
The Difference

Abstract Objective The objective of this study was to review the utilization of a standardized tracheostomy handoff sheet to reduce tracheostomy-related complications. Methods A retrospective chart review was carried out of patients who underwent tracheostomy and had a dedicated tracheostomy handoff sheet utilized in the postoperative period. The handoff sheet contains trach size, backup trach size, airway findings, suction depth, location of maturation suture, location of stay sutures, and photograph of the wound bed on postoperative day 0. An anonymous survey of healthcare providers participating in the patient's care was undertaken regarding the utility of the dedicated trach handoff sheet. Results There were a total of 18 completed questionnaires. The majority of respondents felt the trach handoff sheet was helpful and provided vital information (4.61, scale 1–5). Hundred percent of respondents referenced the handoff sheet at some point during the hospital stay; 83% of respondents (15/18) felt the handoff sheet was more productive than a verbal handoff and 67% of respondents (12/18) preferred the sheet be available bedside rather than a digital format for reference in the electronic medical record. 89% of respondents (16/18) utilized the handoff sheet for wound care. Conclusion There are numerous aspects to proper tracheostomy care. From the immediate postoperative time period to several years out, proper care can make the difference for quality of life, respiratory standpoint, and airway safety. With a daily nursing handoff that at times can become redundant, utilization of a standardized tracheostomy handoff can lead to improve outcomes. These handoff sheets provide information deemed essential to optimal patient care and are always available bedside for review. Standardization and utilization of these tracheostomy sheets have led to decreased airway complications in emergency situations, reduced wound breakdown, and increased safety and efficiency in handoffs.

scholarly journals Seven Different Lighting Conditions in Photogrammetric Studies of a 3D Urban Mock-Up

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8002
Author(s):  
Katarzyna Bobkowska ◽  
Pawel Burdziakowski ◽  
Jakub Szulwic ◽  
Karolina M. Zielinska-Dabkowska
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Total Error ◽  
Spectral Characteristics ◽  
Point Clouds ◽  
Light Sources ◽  
Experimental Proof ◽  
Lighting Conditions ◽  
The Impact

One of the most important elements during photogrammetric studies is the appropriate lighting of the object or area under investigation. Nevertheless, the concept of “adequate lighting” is relative. Therefore, we have attempted, based on experimental proof of concept (technology readiness level—TRL3), to verify the impact of various types of lighting emitted by LED light sources for scene illumination and their direct influence on the quality of the photogrammetric study of a 3D urban mock-up. An important issue in this study was the measurement and evaluation of the artificial light sources used, based on illuminance (E), correlated colour temperature (CCT), colour rendering index (CRI) and Spectral power distribution (SPD) and the evaluation of the obtained point clouds (seven photogrammetric products of the same object, developed for seven different lighting conditions). The general values of the quality of the photogrammetric studies were compared. Additionally, we determined seventeen features concerning the group of tie-points in the vicinity of each F-point and the type of study. The acquired traits were related to the number of tie-points in the vicinity, their luminosities and spectral characteristics for each of the colours (red, green, blue). The dependencies between the identified features and the obtained XYZ total error were verified, and the possibility of detecting F-points depending on their luminosity was also analysed. The obtained results can be important in the process of developing a photogrammetric method of urban lighting monitoring or in selecting additional lighting for objects that are the subject of a short-range photogrammetric study.

scholarly journals Application of different metrics for describing light color quality of white LED

2021 ◽  
Vol 13 (2) ◽  
pp. 31
Author(s):  
Robert Supronowicz ◽  
Jiajie Fan ◽  
Maciej Listowski ◽  
Adam Watras ◽  
Irena Fryc
Keyword(s):  
Thermal Quenching ◽  
Automated System ◽  
Light Sources ◽  
White Led ◽  
Viewing Angle ◽  
Color Quality ◽  
Trade Offs ◽  
Observer Model ◽  
Color Rendering

Using the example of the UV-excited Ca9KMg(PO4)7:1% Eu2+ phosphor, methods for characterizing the color quality of the light emitted by it at different operating temperatures are described. The effect of adopting two different colorimetric observers established by the International Commission on Illumination (i.e., the CIE 1931 observer with a viewing angle of two degrees and the CIE 2015 observer with a viewing angle of ten degrees) on the position of the chromaticity point of light emitted by phosphor is discussed. It was demonstrated that using the CIE 2015 photometric observer to determine the position of the chromaticity point, the tested phosphor is characterized by smaller changes in the color of emitted light as a function of operating temperature than when using the CIE 1931 observer. Full Text: PDF ReferencesR. Pązik et al., "Thermal quenching mechanisms of the Eu3+ luminescence in Ca9Al(PO4)7 obtained by citric route", Materials Research Bulletin, Vol. 48, I.2, 337 (2013). CrossRef I. Fryc, S. W. Brown, Y. Ohno, "A spectrally tunable LED sphere source enables accurate calibration of tristimulus colorimeters", Proc. SPIE Vol. 6158, 125 (2006) CrossRef Y. Ohno, "Practical Use and Calculation of CCT and Duv", LEUKOS, 10:1, 47-55, (2014). CrossRef D. Durmus, "Multi-objective optimization trade-offs for color rendition, energy efficiency, and circadian metrics", Proc. SPIE Vol. 11706, 117061J (2021) CrossRef I. Fryc, D. Czyzewski, " Dokładność pomiarowa spektroradiometrów typu CCD", Przeglad Elektrotechniczny R. 85(11), 276 (2009). DirectLink D. Czyzewski, "Zamienniki LED klasycznych żarówek", Przeglad Elektrotechniczny R. 88(11), 123 (2012). DirectLink J. Kusznier, W. Wojtkowski, "Spectral properties of smart LED lamps", Phot. Lett. Pol., 12(1), 16 (2020). CrossRef P. Hung, J. Y. Tsao, "Maximum White Luminous Efficacy of Radiation Versus Color Rendering Index and Color Temperature: Exact Results and a Useful Analytic Expression", Journ. of Display Techn., 9(6), 405 (2013). CrossRef Y. Asano, MD Fairchild, L. Blondé, "Individual Colorimetric Observer Model", PLOS ONE 11(2) e0145671 (2016). CrossRef Y. Wang, M. Wei, "Preference among light sources with different Duv but similar colour rendition: A pilot study", Lighting Res. & Tech., 50(7), 1013 (2018). CrossRef K. A. G. Smet, "Tutorial: The LuxPy Python Toolbox for Lighting and Color Science", LEUKOS, 16:3, 179 (2020). CrossRef D. Petrisor, C. D. Galatanu, C. Haba, L. Breniuc "Color Quality Measurements of LED Light Sources Using Image Processing", EEEIC/I&CPS Europe, 1, (2019) CrossRef ANSI C78.377:2017 DirectLink I. Fryc, T. Dimitrova-Grekow, "An Automated System for Evaluation of the Quality of Light Sources", 2016 IEEE (Lumen V4), 1 (2016). CrossRef Y. Ohno, "Spectral design considerations for white LED color rendering", Optical Engineering 44(11), 111302 (2005). CrossRef E. Purwanto, P. Dupuis, L. Canale, N. I. Sinisuka, G. Zissis, "Aging study of remote luminophore at ambient temperature", EEEIC/I&CPS Europe, 1 (2019). CrossRef J. Fan, Y. Li, I. Fryc, C. Qian, X. Fan, G. Zhang, "Machine-Learning Assisted Prediction of Spectral Power Distribution for Full-Spectrum White Light-Emitting Diode", IEEE Photonics Journal, 12(1), 1 (2020). CrossRef D. Mozyrska, M. Wyrwas, I. Fryc, "Wyznaczanie parametrów kolorymetrycznych LEDa w pełnym zakresie temperatur pracy", Przeglad Elektrotechniczny R. 93(4a), 232 (2012). CrossRef I. Fryc, "Analiza właściwości spektralnych LEDów z zależności od temperatury i natężenia ich prądu pracy", Przeglad Elektrotechniczny R. 86(10), 187 (2010). DirectLink I. Fryc, "Pomiary wybranych parametrów świetlno-optycznych LEDów według zaleceń Międzynarodowej Komisji Oświetleniowej CIE 127:2007", Przeglad Elektrotechniczny R. 85(11), 317 (2009). DirectLink A. David et al., "Development of the IES method for evaluating the color rendition of light sources", Opt. Express 23, 15888 (2015). CrossRef S Jost-Boissard, P Avouac, M Fontoynont, "Assessing the colour quality of LED sources: Naturalness, attractiveness, colourfulness and colour difference", Lighting Research & Technology, 47(7): 769 (2015). CrossRef J. Kowalska, "Określanie jakości oddawania barw źródeł światła parametrami przedstawionymi w zaleceniach IES TM-30-15 i CIE 013.3-1995", Przeglad Elektrotechniczny R. 93(6), 50 (2017). DirectLink J. Kowalska, I. Fryc, "Jakość oddawania barw współczesnych lamp fluorescencyjnych określona zdefiniowanym przez CIE wskaźnikiem wierności barwy oraz wskaźnikiem oddawania barw", Przeglad Elektrotechniczny R. 95(7), 94 (2019). DirectLink CIE 170-2:2015 DirectLink

scholarly journals The light color quality of LED operating at winter temperatures

2019 ◽  
Vol 11 (4) ◽  
pp. 112 ◽  
Author(s):  
Przemysław Tabaka ◽  
Pawel Rozga
Keyword(s):  
Solid State ◽  
Operating Temperature ◽  
Solid State Lighting ◽  
Light Sources ◽  
Led Light ◽  
Fluorescent Lamps ◽  
Color Rendering ◽  
Incandescent Lamps ◽  
Colour Rendering

The paper presents the results of calculations of colorimetric parameters of LED sources operating at a temperature range from -25oC to 25oC. The chromaticity coordinates and color rendition quality parameters were calculated on the basis of registered spectral distributions of radiation. For individual LED chromaticity shift is illustrated at CIE 1931 x,y diagram with 3 step and 7 step MacAdam ellipses. Full Text: PDF ReferencesJ. P. Freyssinier, D. Frering, J. Taylor, N. Narendran, and P. Rizzo, Reducing lighting energy use in retail display windows. Sixth International Conference on Solid State Lighting, Proceedings of SPIE 6337, 63371L (2006). CrossRef Aman, M. M., et al., 2013. Analysis of the performance of domestic lighting lamps, Energy Policy, CrossRef E. Elijošiute, J. Balciukevičiute, G. Denafas, Life cycle assessment of; compact fluorescent and incandescent lamps: Comparative analysis. Environ Res. Eng. Manag. 61 (3), pp. 65-72, (2012), CrossRef D. Czyzewski, LED substitutes of conventional incandescent lamps Przeglad Elektrotechniczny R. 88, No. 11 (2012), CrossRef P. Tabaka, P. Rozga, Assessment of methods of marking LED sources with the power of equivalent light bulb, ulletin of the Polish Academy of Sciences. Technical Sciences, Vol. 65, No. 6, (2017) CrossRef I. Fryc, P. Jakubowski, K. Kołacz, Analysis of optical radiation parameters of compact discharge HID lamps and LED COB modules used for illuminating shop windows, Przeglad Elektrotechniczny,R. 93, No 11, (2017); pp. 186-189, CrossRef T. Kawabata, Y. Ohno; Optical measurements of OLED panels for lighting applications, pp 1176-1186 Jun 2013, Journal of Modern Optics, Vol. 60, 2013 Issue 14 CrossRef W. Żagan, Conditions necessary to replacing the conventional lamps by energy-saving lamps, Przeglad Elektrotechniczny R. 85, No. 5, pp. 100-104, (2009). DirectLink P. Tabaka; Influence of Ambient Temperature on Colour Properties of Low-Pressure Fluorescent Lamps, Light & Engineering, Vol. 23; No. 2; (2015). DirectLink W. R. Ryckaert, et al., Linear LED tubes versus fluorescent lamps: An evaluation. Energy Build. 49, pp. 429-436. CrossRef M. Zalesinska, J. Zablocka, K. Wandachowicz, Evaluation of Selected Parameters of Non-Directional Household Lamps, Conference: 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4), CrossRef I. Fryc; Measurement techniques of optical LEDs properties performed with compliance conformity with CIE 127:2007 standard, Przeglad Elektrotechniczny R. 85, No. 11, pp. 317-319, (2009) DirectLink IESNA, IES Approved Method: Measuring Lumen Maintenance of LED Light Sources. IES LM-80-08', IES Subcommittee on Solid-State Lighting of the IES Testing Procedures Committee (2018). DirectLink D. B. Judd, Estimation of chromaticity differences and nearest color temperature on the standard 1931 ICI colorimetric coordinate system. J. Opt. Soc. America 26 (11), 421, (1936) CrossRef CIE 177:2007 Colour Rendering of White LED Light Sources DirectLink CIE 13.3-1995 Method of Measuring and Specifying Colour. DirectLink CIE 224:2017 Colour Fidelity Index for accurate scientific use DirectLink CIE 15:2004 Colorimetry. DirectLink D. Mozysrska, M. Wyrwas, I. Fryc, The determination of the LEDs colorimetric parameters, in the range of their operating temperature, Przeglad Elektrotechniczny, R. 93, No. 4a, pp. 232-234, (2012). DirectLink J. Kowalska, Analysis of parameters describing the quality of the color rendering of light sources according to the IES TM-30-15 and the CIE 013.3-1995, Przeglad Elektrotechniczny, R. 93, No. 6; pp. 50-54, (2017) CrossRef J. Kowalska, I. Fryc, Colour rendition quality of typical fluorescent lamps determined by CIE Colour Fidelity Index and Colour Rendering Index, Przeglad Elektrotechniczny, R. 95, No. 7; (2019), pp. 94-97 CrossRef J. Kowalska, Ambiguity and limitations in determining the quality of the color rendering of light sources by index Ra (CIE CRI), Przeglad Elektrotechniczny, R. 93 No. 5, pp. 74-78, (2017) CrossRef I. Fryc, J. Fryc, A. Wasowski, Considerations about determining color rendering of light sources, Przeglad Elektrotechniczny, R. 92 No. 2, pp. 218-223, (2016) CrossRef I. Fryc, LED's spectral power distribution under different condition of operating temperature and driving current, Przeglad Elektrotechniczny, R. 86, No. 10, pp. 187-189, (2010). DirectLink A. David, P. Fini, K. Houser et al., Development of the IES method for evaluating the color rendition of light sources, Optics Express; Vol. 23; Issue 12, pp. 15888-15906, (2015). CrossRef K. Houser, M. Mossman, K. Smet et al, Tutorial, Color Rendering and Its Applications in Lighting, LEUKOS; Vol. 12, Issue 1-2; pp. 7-26; (2016). CrossRef

PROBLEMS AND PROSPECTS OF LED LAMP RETROPHYTES

2020 ◽  
pp. 48-52
Author(s):  
I. I. Bayneva ◽  
I. A. Lychagin
Keyword(s):  
Form Factor ◽  
Energy Savings ◽  
Calculated Data ◽  
Light Distribution ◽  
Light Sources ◽  
Potential Hazard ◽  
Direct Replacement ◽  
The Difference ◽  
Incandescent Lamps

The article discusses modern light sources – LED retrofit lamps, which are used to replace traditional light sources (incandescent, fluorescent lamps). The article provides calculated data showing energy savings as a result of replacing traditional light sources with LED ones. LEDs have undeniable advantages over such light sources. This is a high luminous efficiency, durability, color reproduction and much more. Ample opportunities for direct replacement of LED lamps are associated with their form factor, which is the same as that of traditional light sources. The main parameters of the form factor in this case are the sizes of the light sources (bulb diameter) and the type of cap. However, direct replacement has many controversial sides. Firstly, the light environment created by traditional incandescent lamps is very different from that for LED light sources due to the difference in their spectral light distribution. Secondly, the light intensity curves of LED and traditional light sources are very different in a number of cases. Therefore, direct replacement must be carried out very carefully, taking into account the final light distribution of the light device, where they are used. Thirdly, due to the incompleteness of research in the field of safety of LED lighting, the use of such light sources can be limited due to the potential hazard that may lead to a decrease in labor productivity and quality of life. Fourth, the design of LED lamps is complex, their quality depends on the quality of LEDs, phosphors and electronics, so consumer properties may not be at the highest level, even at fairly high prices. Fifthly, for any, even the simplest LED lamp, a heat sink system is necessary, since the thermal regime of the lamps imposes certain restrictions on their use.

Automatic White Balance of Digital Camera Based on Global Probability Distribution

2012 ◽  
Vol 433-440 ◽  
pp. 5443-5447 ◽  
Author(s):  
Hui Nan Guo ◽  
Jian Zhong Cao
Keyword(s):  
Probability Distribution ◽  
Color Image ◽  
Digital Camera ◽  
Light Sources ◽  
Digital Cameras ◽  
White Balance ◽  
Hsi Color Model ◽  
The Difference ◽  
True Colors ◽  
Automatic White Balance

The white balance is an important parameter of digital camera which makes a great impact on the application of digital cameras. However, due to the limitations of hardware of digital camera, the output image of digital camera cannot restore true colors of the objects under the different light sources conditions. And existing automatic white balance (AWB) algorithms have many application restrictions, particularly the single color image, the algorithms always failure to adjust. To solve this problem, this paper proposes an optimized algorithm based on the gray world assumption and HSI color model. According to the R, G and B color components probability distribution, the algorithm adjusts the image by using the difference value of color. Experimental results show that our algorithm can adjust images in complex situations; meanwhile these confirm that this method is not only effective, but also has the advantage of easy realization.

Evaluation of Color Rendering Index for LED and Fluorescent Light Sources

2015 ◽  
Vol 731 ◽  
pp. 22-26
Author(s):  
Huan Jiang ◽  
Min Huang ◽  
Fu Song Yang ◽  
Yu Liu
Keyword(s):  
Light Emitting Diode ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Color Science ◽  
Color Rendering Index ◽  
Different Color ◽  
Color Rendering

In order to assess the performances of different color rendering index (Ra, CRI, CQS, nCRI, R96a). The LED (light-emitting diode), fluorescent light sources and 30 printed color samples were used in our experiment. 20 observers were organized to carry out the color preference experiment, the visual data were accumulated to test the performances of the light sources and the results indicated that existing color rendering index have some deficiencies to assess the quality of the light source, which were needed to be modified for the theory of color science and industry application. The new CQS additional scales were calculated and the improvements were still insufficient for the LED light sources.

The Difference of Jadeite-Jade Lavender under Three Light Sources

2013 ◽  
Vol 544 ◽  
pp. 493-496
Author(s):  
Jia Hui Zhao ◽  
Da Peng Chen ◽  
Ying Guo ◽  
Shuang Wang
Keyword(s):  
Light Source ◽  
Color Index ◽  
Color Space ◽  
Fluorescent Light ◽  
Light Sources ◽  
Transaction Process ◽  
Color Differences ◽  
Purple Color ◽  
The Difference

Compare the different appearance of jadeite-jade with three standard light sources, daylight D65,incandescent light A and fluorescent light F2(CWF),whose colors are purple to bluish violet with low chroma and low lightness in. The analysis of color index in the CIE 1976L* a* b uniform color space shows that the hue of lavender is influence by the light of standard light sources, followed by chroma, simultaneously value is seldom influenced obviously. And the color saturation of purple jade samples with CWF is usually higher, showing more vivid purple. However, D65 is benefit to the lightness of the purple jade, in which the average of color differences is known as the largest while the variance is the smallest. As D65 can be used to distinguish the purple color of jade samples most greatly, it is intended to be the best light source for appreciation of jadeite-jade. In consideration of the better quality of the purple color displayed with the CWF, it can be used during business transaction process.

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