Human eye color difference threshold measurement system

2013 ◽  
Author(s):  
Lin Liu ◽  
Taogeng Zhou
Keyword(s):  
Measurement System ◽  
Color Difference ◽  
Difference Threshold ◽  
Eye Color ◽  
Human Eye ◽  
Threshold Measurement

The Effect of Liner Thickness on the Color of Y-TZP Based All-Ceramic Restorations

2013 ◽  
Vol 544 ◽  
pp. 380-383
Author(s):  
Ruo Yu Liu ◽  
Yao Kun Zhang ◽  
Shan Yu Zhou ◽  
Chen Hu ◽  
Dong Dong Jing ◽  
...  
Keyword(s):  
Color Difference ◽  
Core Material ◽  
Control Group ◽  
Ceramic System ◽  
Eye Color ◽  
Human Eye ◽  
Color Parameters ◽  
All Ceramic ◽  
Ceramic Restorations ◽  
Different Thickness

To evaluate the effect of various liner thickness on the color of Y-TZP based all-ceramic restorations. Forty disc specimens (10 mm diameter, 0.5 mm thick) were fabricated from IPS e.max ZirCAD core material. The specimens were randomly divided into four groups (n=10) according to layering with different ZL1 IPS e.max ZirLiner thicknesses as: 0.1 mm, 0.2 mm, 0.3 mm and one group had received no treatment as the control group. And 0.6 mm veneering porcelain was fired on the IPS e.max ZirCAD core material by traditional layering technique. Using a spectrophotometer to measure Color parameters L, a and b of the specimens after veneered. ΔE were calculated to compare color difference among the four groups. Intergroup differences of ΔE in different thicknesses were statistically significant at P<0.05. The ΔE between groups with different thickness were 2.03±0.07, 2.88±0.07, 3.54±0.07, 0.86±0.06, 1.47±0.06 and 0.67±0.06 respectively.Usually researchers apply ΔE=1.5 as the threshold for distinguishing two different colors by the human eye. Color difference ΔE between different groups with and without liner application was more than 1.5, which was in the perceptible range, but ΔE of liner application with the thickness of 0.1 mm, 0.2 mm and 0.3 mm were undistinguishable by human eye (ΔE<1.5). Thus liner application of the all ceramic system could significantly affected the final color of the all ceramic restorations and it ameliorated esthetics of Y-TZP all-ceramic restorations to good purpose. However, Changes in the thickness (0.1 mm-0.3 mm) of liner application have no significant effect on the final shade of Y-TZP based all-ceramic restorations.

scholarly journals Genome-wide association study in almost 195,000 individuals identifies 50 previously unidentified genetic loci for eye color

2021 ◽  
Vol 7 (11) ◽  
pp. eabd1239
Author(s):  
Mark Simcoe ◽  
Ana Valdes ◽  
Fan Liu ◽  
Nicholas A. Furlotte ◽  
David M. Evans ◽  
...  
Keyword(s):  
Association Study ◽  
Genome Wide Association Study ◽  
Color Variation ◽  
Genome Wide Association ◽  
Nucleotide Polymorphisms ◽  
Melanin Pigmentation ◽  
Eye Color ◽  
Human Eye ◽  
Genome Wide ◽  
Genomic Regions

Human eye color is highly heritable, but its genetic architecture is not yet fully understood. We report the results of the largest genome-wide association study for eye color to date, involving up to 192,986 European participants from 10 populations. We identify 124 independent associations arising from 61 discrete genomic regions, including 50 previously unidentified. We find evidence for genes involved in melanin pigmentation, but we also find associations with genes involved in iris morphology and structure. Further analyses in 1636 Asian participants from two populations suggest that iris pigmentation variation in Asians is genetically similar to Europeans, albeit with smaller effect sizes. Our findings collectively explain 53.2% (95% confidence interval, 45.4 to 61.0%) of eye color variation using common single-nucleotide polymorphisms. Overall, our study outcomes demonstrate that the genetic complexity of human eye color considerably exceeds previous knowledge and expectations, highlighting eye color as a genetically highly complex human trait.

Verification of In Situ Thresholds and Integrated Real-Ear Measurements

2010 ◽  
Vol 21 (10) ◽  
pp. 663-670 ◽  
Author(s):  
Jeffrey J. DiGiovanni ◽  
Ryan M. Pratt
Keyword(s):  
Measurement System ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Analysis Tool ◽  
Ohio University ◽  
Positive Direction ◽  
Significant Difference ◽  
Threshold Measurement

Background: Accurate prescriptive gain results in a more accurate fit, lower return rate in hearing aids, and increased patient satisfaction. In situ threshold measurements can be used to determine required gain. The Widex Corporation uses an in situ threshold measurement strategy, called the Sensogram. Real-ear measurements determine if prescriptive gain targets have been achieved. Starkey Laboratories introduced an integrated real-ear measurement system in their hearing aids. Purpose: To determine whether the responses obtained using the Widex Sensogram were equivalent to those obtained using current clinical threshold measurement methods. To determine the accuracy of the Starkey IREMS™ (Integrated Real Ear Measurement System) in measuring RECD (real-ear to coupler difference) values compared to a dedicated real-ear measurement system. Research Design: A verification design was employed by comparing participant data measured from standard, benchmark equipment and procedures against new techniques offered by hearing-aid manufacturers. Study Sample: A total of 20 participants participated in this study. Ten participants with sensorineural hearing loss were recruited from the Ohio University Hearing, Speech, and Language Clinic participated in the first experiment. Ten participants with normal hearing were recruited from the student population at Ohio University participated in both experiments. The normal-hearing group had thresholds of 15 dB HL or better at the octave frequencies of 250–8000 Hz. The hearing-impaired group had thresholds of varying degrees and configurations with thresholds equal to or poorer than 25 dB HL three-frequency pure-tone average. Data Collection and Analysis: The order of measurement method for both experiments was counterbalanced. In Experiment 1, thresholds obtained via the Widex Sensogram were compared to thresholds obtained for each participant using a clinical audiometer and ER-3A insert ear phones. In Experiment 2, RECD values obtained via the Starkey IREMS were compared to RECD values obtained via the Audioscan Verifit™. A repeated-measures analysis of variance (ANOVA) was used for statistical analysis, and a Fisher's LSD (least significant difference) was used as a post hoc analysis tool. Results: A significant difference between Sensogram thresholds and conventional audiometric thresholds was found with the Sensogram method resulting in better threshold values at 0.5, 1.0, and 2.0 kHz for both groups. In Experiment 2, a significant difference between RECD values obtained by the Starkey IREMS and the Audioscan Verifit system was found with significant differences in RECD values found at 0.25, 0.5, 0.75, 1.5, 2.0, and 6.0 kHz. Conclusions: The Sensogram data differ significantly from traditional audiometry at several frequencies important for speech intelligibility. Real-ear measures are still required for verification of prescribed gain, however, calling into question any claims of shortened fitting time. The Starkey IREMS does perform real-ear measurements that vary significantly from benchmark equipment. These technologies represent a positive direction in prescribing accurate gain during hearing-aid fittings, but a stand-alone system is still the preferred method for real-ear measurements in hearing-aid fittings.

scholarly journals Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci

PLoS Genetics ◽  
2010 ◽  
Vol 6 (5) ◽  
pp. e1000934 ◽  
Author(s):  
Fan Liu ◽  
Andreas Wollstein ◽  
Pirro G. Hysi ◽  
Georgina A. Ankra-Badu ◽  
Timothy D. Spector ◽  
...  
Keyword(s):  
Genetic Association ◽  
Eye Color ◽  
Human Eye ◽  
Digital Quantification

Cathode-Ray Tube Color Perceptible Color Difference Threshold Evaluation in Visual Color Matching

2008 ◽  
Vol 28 (3) ◽  
pp. 599-603 ◽  
Author(s):  
黄敏 Huang Min ◽  
廖宁放 Liao Ningfang ◽  
刘浩学 Liu Haoxue ◽  
徐艳芳 Xu Yanfang
Keyword(s):  
Color Difference ◽  
Difference Threshold ◽  
Color Matching ◽  
Visual Color ◽  
Cathode Ray Tube

Color-Difference Threshold for Printed Images

2013 ◽  
Vol 469 ◽  
pp. 236-239
Author(s):  
Hao Xue Liu ◽  
Gui Hua Cui ◽  
Min Huang ◽  
Bing Wu ◽  
Yu Liu
Keyword(s):  
Color Difference ◽  
Psychophysical Experiment ◽  
Difference Threshold ◽  
Test Image ◽  
Color Distribution ◽  
Difference Formula ◽  
Color Differences ◽  
The Mean ◽  
Image Pairs ◽  
Test Color

Five ISO 400 images were used as test images and a method of limits psychophysical experiment was designed to test color-difference threshold in printed images. The color appearance of each original image was modified by an exponential function for CIELAB lightness and chroma, an offset function for CIELAB hue at 20 steps for each attributes respectively. The modified images and their originals were paired to form the test image pairs. The mean color differences of image pairs, ranged from 0 to 4 CIELAB units, were calculated by CIELAB color-difference formula and nearly uniformly divided into 21 grades for each attributes. The test image pairs were assessed in a CPC-8n lighting booth. 12 normal color vision observers took part in the experiment. The experimental results showed that the mean color-differences threshold for lightness, chroma and hue attributes were 1.49, 1.53 and 0.78 CIELAB units showing the threshold for hue was apparently smaller than that of lightness and chroma, and the thresholds of different images were dependent on the image content or color distribution.

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