Application of the CIECAM02 colour appearance model to predict the effect of gamma on the colours viewed on CRT monitors

2004 ◽  
Vol 19 (10) ◽  
pp. 1029-1045 ◽  
Author(s):  
Snjezana Soltic ◽  
Andrew N. Chalmers ◽  
Radhika Jammalamadaka
Keyword(s):  
Appearance Model ◽  
Colour Appearance

Colour Image Enhancement using Perceptual Saturation and Vividness

2019 ◽  
Vol 2019 (1) ◽  
pp. 243-246
Author(s):  
Muhammad Safdar ◽  
Noémie Pozzera ◽  
Jon Yngve Hardeberg
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Test Performance ◽  
Appearance Model ◽  
Colour Space ◽  
Categorical Judgment ◽  
Saturation Scale ◽  
Colour Image ◽  
Colour Appearance ◽  
Future Test

A perceptual study was conducted to enhance colour image quality in terms of naturalness and preference using perceptual scales of saturation and vividness. Saturation scale has been extensively used for this purpose while vividness has been little used. We used perceptual scales of a recently developed colour appearance model based on Jzazbz uniform colour space. A two-fold aim of the study was (i) to test performance of recently developed perceptual scales of saturation and vividness compared with previously used hypothetical models and (ii) to compare performance and chose one of saturation and vividness scales for colour image enhancement in future. Test images were first transformed to Jzazbz colour space and their saturation and vividness were then decreased or increased to obtain 6 different variants of the image. Categorical judgment method was used to judge preference and naturalness of different variants of the test images and results are reported.

Testing Colour Appearance Model Based UCS Using HDR, WCG and COMBVD Datasets

2021 ◽  
Vol 2021 (29) ◽  
pp. 381-386
Author(s):  
Xu Qiang ◽  
Muhammad Safdar ◽  
Ming Ronnier Luo
Keyword(s):  
Correlation Coefficient ◽  
Power Factor ◽  
Marked Improvement ◽  
Appearance Model ◽  
Colour Difference ◽  
Similar Performance ◽  
Model Based ◽  
Test Models ◽  
Appearance Models ◽  
Colour Appearance

Two colour appearance models based UCSs, CAM16-UCS and ZCAM-QMh, were tested using HDR, WCG and COMBVD datasets. As a comparison, two widely used UCSs, CIELAB and ICTCP, were tested. Metrics of the STRESS and correlation coefficient between predicted colour differences and visual differences, together with local and global uniformity based on their chromatic discrimination ellipses, were applied to test models' performance. The two UCSs give similar performance. The luminance parametric factor kL, and power factor γ, were introduced to optimize colour-difference models. Factors kL and γ of 0.75 and 0.5, gave marked improvement to predict the HDR dataset. Factor kL of 0.3 gave significant improvement in the test of WCG dataset. In the test of COMBVD dataset, optimization provide very limited improvement.

Hierarchical tone mapping based on image colour appearance model

2014 ◽  
Vol 8 (4) ◽  
pp. 358-364 ◽  
Author(s):  
Jinsheng Xiao ◽  
Wenhao Li ◽  
Guoxiong Liu ◽  
Shih‐Lung Shaw ◽  
Yongqin Zhang
Keyword(s):  
Appearance Model ◽  
Tone Mapping ◽  
Colour Appearance

A Colour Appearance Model based on Jzazbz Colour Space

2018 ◽  
Vol 2018 (1) ◽  
pp. 96-101
Author(s):  
Muhammad Safdar ◽  
Jon Y. Hardeberg ◽  
Youn Jin Kim ◽  
Ming Ronnier Luo
Keyword(s):  
Appearance Model ◽  
Colour Space ◽  
Model Based ◽  
Colour Appearance

New Metrics for Evaluating Whiteness of Fluorescent Samples

2019 ◽  
Vol 2019 (1) ◽  
pp. 247-251
Author(s):  
Lv X. ◽  
Wang Y.Z. ◽  
M. Wei ◽  
Luo M.R.
Keyword(s):  
Magnitude Estimation ◽  
Independent Set ◽  
Accurate Prediction ◽  
The Other ◽  
Appearance Model ◽  
Low Level ◽  
Adaptation Factor ◽  
Colour Appearance

A magnitude estimation experiment was carried out to scale the extent of whiteness from a set of near white textile samples including fluorescent white agent. Each was assessed under 4 different CCTs, each having a high and a low level of UV energy. The results were used to test various existing whiteness formulae. Finally, by fitting to the present data, two new metrics were developed. One is based on CIECAM02, and the other is based on the present CIE whiteness formula by transforming the data to D65 chromaticity from the other white sources via CAT02 chromatic adaption transform with a proper incomplete adaptation factor (D). It was also tested using an independent set of data. Both formulae gave accurate prediction to the data. The former metric is proposed because it is based on a colour appearance model.

Assessing glare, Part 3: Glare sources having different colours

2016 ◽  
Vol 50 (4) ◽  
pp. 596-615 ◽  
Author(s):  
Y Yang ◽  
Ronnier M Luo ◽  
WJ Huang
Keyword(s):  
Light Emitting Diodes ◽  
Luminous Efficiency ◽  
Appearance Model ◽  
White Led ◽  
Light Emitting ◽  
Discomfort Glare ◽  
Colour Appearance ◽  
Visual Results

This paper describes an experiment for assessing the discomfort glare caused by light emitting diodes (LEDs) having different colours. The results showed that coloured LEDs induce more discomfort glare than a white LED. On comparing different coloured LEDs, blue ones gave the highest glare perception, especially for those having shorter peak wavelengths. Different earlier proposed luminous efficiency functions for discomfort glare were applied to re-define luminance. This led to modified unified glare ratings, which achieved very accurate predictions of the visual results. A modified brightness based on a colour appearance model for unrelated lights was used to predict glare and also performed very well.

Indoor lighting quality: Effects of different wall colours

2016 ◽  
Vol 49 (1) ◽  
pp. 33-48 ◽  
Author(s):  
L Bellia ◽  
A Pedace ◽  
F Fragliasso
Keyword(s):  
Spectral Irradiance ◽  
Appearance Model ◽  
Test Room ◽  
Human Eye ◽  
Indoor Lighting ◽  
The Impact ◽  
Colour Appearance

This paper reports the results of measurements performed in a test room to investigate the impact of using different wall colours and light scenes on indoor lighting quality. Eye level spectral irradiances were measured for a user located inside the room and seated at a desk. These measurements allow the use of the Irradiance Toolbox, which makes it possible to calculate equivalent illuminances for the photopigments in the human eye. Moreover, the CIECAM02 colour appearance model was used to investigate the variations in hue and chroma values of the different wall colours when changing the light scene. The results demonstrate that there are significant variations in eye level spectral irradiance distributions, photoreceptor stimulation and hue and chroma values with different combinations of wall colours and light scenes.

Sign in / Sign up

Export Citation Format

Share Document