Projects

A model of spatio-chromatic contrast sensitivity under mesopic and photopic light levels and its applications

Sophie Wuerger, Maliha Ashraf, Minjung Kim, Jasna Martinovic, María Pérez-Ortiz, Rafał K. Mantiuk

Abstract

Contrast sensitivity functions (CSFs) characterize the sensitivity of the human visual system at different spatial frequencies. However, little is known about CSFs at luminances above 1000 cd/m², especially for color. Here, we measured contrast sensitivities at background luminances from 0.02 cd/m² to 7000 cd/m² and for three color directions (black-white or achromatic, red-green, and yellow-violet). Stimuli were Gabor patches of various spatial frequencies (0.125 to 6 cpd), displayed on a high dynamic range display (peak luminance: 15,000 cd/m²). We found that achromatic contrast sensitivity has an inverted U-shape as a function of background luminance, with peak sensitivity at 200 cd/m², while red-green and yellow-violet contrast sensitivities were monotonic functions of background luminance, saturating at 200 cd/m². Based on these measurements, we developed a model that predicts contrast sensitivity for the average observer. This model is intended for applications in high dynamic range imaging.

Materials

Data
Code for the JoV paper model - the model predicts contrast sensitivity for the three colour directions in the DKL colour space and was fitted to the data presented in the JoV paper.
Code for the CIC paper model - the model predicts contrast sensitivity for any colour direction and was fitted to 5 independent datasets, as described in the CIC28 paper.

Journal paper

[download] Wuerger, Ashraf, Kim, Martinovic, Perez-Ortiz and Mantiuk. (2020). Spatio-chromatic contrast sensitivity under mesopic and photopic light levels. Journal of Vision.20(4):23. doi:10.1167/jov.20.4.23.

Conference papers

[download] Kim, Ashraf, Perez-Ortiz, Martinovic, Wuerger and Mantiuk. (2020). Contrast sensitivity functions for HDR displays.

http://www.imaging.org/site/IST/IST/Conferences/LIM/LIM_Home.aspx

[download] Rafał K. Mantiuk, Minjung Kim, Maliha Ashraf, Qiang Xu, M. Ronnier Luo, Jasna Martinovic and Sophie Wuerger. Practical color contrast sensitivity functions for luminance levels up to 10000 cd/m². In: Color Imaging Conference (CIC28), 2020
[download] Maliha Ashraf, Sophie Wuerger, Minjung Kim, Jasna Martinovic, and Rafał K. Mantiuk. Spatio-chromatic contrast sensitivity across the lifespan: interactions between age and light level in high dynamic range. In: Color Imaging Conference (CIC28), 2020
[download] Minjung Kim, Maryam Azimi and Rafał K. Mantiuk. Perceptually motivated model for predicting banding artefacts in high-dynamic range images In: Color Imaging Conference (CIC28), 2020
[download] Minjung Kim, Maryam Azimi and Rafał K. Mantiuk. Color Threshold Functions: Application of Contrast Sensitivity Functions in Standard and High Dynamic Range Color Spaces In: Human Vision and Electronic Imaging, 2021

Talks

[download] Ashraf, M., Wuerger, S. M., Mantiuk, R. K., and Martinovic, J. (2019). Luminance and chromatic contrast sensitivity at high light levels. I-Perception, 10, 5. doi:10.1177/2041669519854233
Wuerger, S., Ashraf, M., Mantiuk, R. K., Kim, M., and Martinovic, J. (2019). Luminance and Chromatic Contrast Sensitivity at an Extended Luminance Range. Oral Presentation at the 25th Symposium of the International Colour Vision Society (ICVS), 5-9 July 2019, Riga, Latvia. https://www.icvs2019.lu.lv/.

Posters

[download] Perez-Ortiz, Martinovic, Mantiuk, and Wuerger. (2019). Luminance and Chromatic Contrast Sensitivity at High Light Levels. Perception.
[download] Ashraf, M., Wuerger, S. M., Mantiuk, R. K., Kim, M., and Martinovic, J. (2019). Luminance-dependent spatio-chromatic sensitivity: from detection to appearance. Poster Presentation at Leeds Colour Conference, 29-30 July 2019, Leeds, UK. http://stephenwestland.co.uk/colour2019/
[download] Wuerger, Mantiuk, Perez-Ortiz and Martinovic. (2019). Luminance and chromatic contrast sensitivity at high light levels. Journal of Vision. 19(10):70b. doi:10.1167/19.10.70b.
[download] Ashraf, M., Wuerger, S., Mantiuk, R. K., Kim, M., and Martinovic, J. (2019). Luminance and chromatic contrast sensitivity for extended range of light levels. Poster Presentation at Liverpool Neuroscience Day (LND), 14 June 2019, Liverpool, UK. https://lng.org.uk/event/lnd2019/
[download] Ashraf, M., Wuerger, S. M., Mantiuk, R. K., Kim, M., Saunderson, H., and Martinovic, J. (2019). Age-related changes in spatio-chromatic contrast sensitivity at mesopic and photopic light levels. Poster Presentation at Women in Vision UK Meeting, 13 December 2019, Belfast, UK. Retrieved from https://www.networcuk.com/Home/WomenInVision