Computer Laboratory

Projects

A Model of Spatio-Chromatic Sensitivity under Mesopic and Photopic Light Levels

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


Figure 1. A model of spatio-chromatic sensitivity under mesopic and photopic light levels.

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

Publications

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


Figure 2. HDR display.

Figure 3. Sample stimuli.

Figure 4. Contrast sensitivity measurements as a function of frequency.

Figure 5. Contrast sensitivity measurements as a function of luminance.

Contact

Please contact Rafał Mantiuk or Sophie Wuerger.