The CIE colour rendering index (CRI) has been criticized for its poor correlation with the visual colour rendering of many spiked or narrowband sources, its outdated colour space and chromatic adaptation transform and the use of a small number of non-optimal reflectance samples that have enabled lamp manufacturers to tune the spectrum of a light source to yield, in some cases, inappropriately high general CRI values. The CRI2012 metric proposed in this paper addresses these criticisms by combining the most state of the art colorimetric colour difference model, i.e. CAM02-UCS, with a mathematical reflectance set that exhibits a highly uniform spectral sensitivity. A set of 210 real reflectance samples has also been selected to provide additional information on the expected colour shifts when changing illumination.
The perception and measurement of gloss is just one part of the concept of appearance measurement. We describe the comparison between data derived by 20 observers who each scaled the perceived gloss of a set of 84 neutral and colored test samples and measurements of those samples made using a glossmeter and a sphere-based spectrophotometer. With a glossmeter, the relationship between the visual-scaled data and the measured gloss values could be described by a three-part linear fit or, with a higher correlation, a cubic function. For the sphere-based spectrophotometer, the difference in the luminance factor, deltaY, between specular-included and specular-excluded measurements, was found to give a better linear correlation with the observer-scaled data. The color of the samples did not appear to significantly change the perceived gloss of the surface.
Abstract:The effect of cross-regional or cross-cultural differences on color appearance ratings and memory colors of familiar objects was investigated in seven different countries/regions -Belgium, Hungary, Brazil, Colombia, Taiwan, China and Iran. In each region the familiar objects were presented on a calibrated monitor in over 100 different colors to a test panel of observers that were asked to rate the similarity of the presented object color with respect to what they thought the object looks like in reality (memory color). For each object and region the mean observer ratings were modeled by a bivariate Gaussian function. A statistical analysis showed significant (p < 0.001) differences between the region average observers and the global average observer obtained by pooling the data from all regions. However, the effect size of geographical region or culture was found to be small. In fact, the differences between the region average observers and the global average observer were found to of the same magnitude or smaller than the typical within region inter-observer variability. Thus, although statistical differences in color appearance ratings and memory between regions were found, regional impact is not likely to be of practical importance.
WHAT THIS PAPER ADDS Using a structured assessment tool, this review objectively assesses the quality of current venous leg ulcer clinical practice guidelines (CPGs) to assist healthcare professionals in choosing a high quality CPG to advise their practice. The authors have also identified shortfalls that can be addressed with the aim of improving future editions of CPGs. This review has identified a number of CPGs that are methodologically sound and recommended for clinical use. It also identifies specific areas for refinement in the other included CPGs, and this information may be used to guide CPG developers in future versions.Objective: The aim was to evaluate the quality of current venous leg ulcer (VLU) clinical practice guidelines (CPGs) to assist healthcare professionals in choosing an accessible high quality CPG to advise their practice, and to identify areas for improvement in future versions of current CPGs. Methods: A systematic review of PubMed, Embase, online CPG databases, and reference lists of included CPGs was carried out. Full text CPGs published no earlier than 1998 reporting evidence based recommendations on VLU diagnosis and management in English were included. CPGs that were only available if purchased were excluded. Two reviewers identified eligible CPGs, extracted data, and assessed the quality independently using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument. Significant scoring discrepancies were discussed with a third reviewer. Results: Fourteen eligible CPGs were identified (1999e2016). The majority of CPGs originated from Europe or North America. Overall, there was good inter-reviewer reliability of scores with an intraclass correlation coefficient of 0.986 (95% confidence interval 0.979e0.991). No single CPG achieved the highest score in all six domains. Significant methodological heterogeneity was observed across VLU CPGs; however, consistently, poor performance was noted in domain 5, concerning CPG applicability. Conclusion: Four CPGs were considered of adequate quality for clinical use. Consolidation of efforts to drive high quality, comprehensive VLU CPGs is necessary to reduce the number of and heterogeneity seen in currently published guidelines. Elements of methodological quality are lacking and a structured approach with use of checklists and CPG creation tools, such as AGREE II or others, may bolster rigour in future VLU CPGs.
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