A spatio-chromatic colour appearance model for retargeting high dynamic range image appearance across viewing conditions

Lead Research Organisation: University of Aberdeen
Department Name: Psychology

Abstract

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Description Our data demonstrate a previously unknown characteristic of the visual system at high luminance. Using the data, we developed a new, fundamental model of the human visual system (the spatio-chromatic sensitivity function) that can predict the visibility of black-and-white and colour patterns under very dim (0.02 cd/m^2) and very bright (10,000 cd/m^2) viewing conditions. We are currently investigating the application of the model in several problems, including high-dynamic-range video compression and modelling of colour appearance.
Exploitation Route Our work has implications for improving future HDR image and video coding standards. Our work can also help to design better colour spaces and metrics for high-dynamic-range content.

One of such metrics was presented in a recently published SIGGRAPH paper: http://dx.doi.org/10.1145/3450626.3459831
Sectors Creative Economy,Electronics
URL https://www.cl.cam.ac.uk/research/rainbow/projects/hdr-csf/
 
Description Our new CSF function and the related research on models of banding have lead to the development of two important quality metrics, now widely used in the industry (video compression, method evaluation, display engineering, AR/VR modeling): PU21 and FovVideoVDP. PU21: A novel perceptually uniform encoding for adapting existing quality metrics for HDR: http://dx.doi.org/10.1109/PCS50896.2021.9477471 https://github.com/gfxdisp/pu21 FovVideoVDP: A visible difference predictor for wide field-of-view video: http://dx.doi.org/10.1145/3450626.3459831 https://www.cl.cam.ac.uk/research/rainbow/projects /fovvideovdp/ The work also raised the interest from the industry, which expressed a desire to fund follow-up research.
First Year Of Impact 2021
Sector Digital/Communication/Information Technologies (including Software),Electronics
 
Description eastbio doctoral training programme
Amount £50,000 (GBP)
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2018 
End 08/2022
 
Description responsive mode
Amount £343,632 (GBP)
Funding ID BB/R009287/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2018 
End 04/2021
 
Title Code for the HDR model based on CSF human participant data 
Description This is the model associated with the JoV and LIM 2020 publications. It predicts the CSF for achromatic and chromatic stimuli of arbitrary size against a range of background luminances, thus being potentially useful for HDR imaging. 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? Yes  
Impact The papers are currently in press so the impacts are likely to materialise in the future, once they've reached a wider audience. 
URL https://github.com/MalihaAshraf/CSF_luminance_model
 
Title Measurements of spatio-chromatic contrast sensitivity up to 7000 cd/m^2 
Description This dataset contains contrast measurements at luminances from 0.02 cd/m^2 (mesopic) to 7000 cd/m^2 (photopic). The stimuli were Gabor patches at f = 0.5, 1, 2, 4, 6 cpd in three colour directions. Please refer to README.md for further details. For more information, please also see the project page: https://www.cl.cam.ac.uk/research/rainbow/projects/hdr-csf/ 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact Our new CSF function and the related research on models of banding have lead to the development of two important quality metrics, now widely used in the industry (video compression, method evaluation, display engineering, AR/VR modeling): 1) PU21, a novel perceptually uniform encoding for adapting existing quality metrics for HDR and 2) FovVideoVDP: A visible difference predictor for wide field-of-view video. 
URL https://www.repository.cam.ac.uk/handle/1810/304228
 
Description Cafe Scientifique: Display technologies: A perspective from vision science 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact This was a Cafe Scientifique format event that discussed how knowledge about human perception can feed into development of cutting-edge display technologies, such as HDR television. A half hour talk was followed up by 45 minute discussion. The audience was assessed whether they increased their knowledge and were also given an opportunity to join a participant panel so that they can volunteer in studies on perception if they so wish.
Year(s) Of Engagement Activity 2019
URL https://www.abdn.ac.uk/the-north/events/14310/
 
Description Colour Perception public talk (Perthshire Society for Natural Science) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact 60 people attended a public talk covering various topics in colour perception research and connecting them to a broader theme of scientific interdisciplinarity in action, by integrating and referring to findings from physiology, optics, engineering and psychology. A 45 minute talk was followed by a vibrant 40 minute discussion and the audience and organisers were left keenly interested in more detail on certain aspects of colour science, planning to engage further speakers on this topic.
Year(s) Of Engagement Activity 2023
 
Description Focus groups with older adults: displays and technology 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The purpose of this focus group is to establish the needs of older adults when it comes to display technologies, in particular concerning tablets. 4 older adults attended and discussed their use of display devices and were given an opportunity to try out and comment on software for adjustments of colour or sharpness, such as those that will be coming out of our own project. We will conduct 3 more focus groups such as these in the next months, and we plan to compile the data resulting from the groups into a publishable outcome, even though the groups were initially conceived simply as a form of public engagement.
Year(s) Of Engagement Activity 2018
 
Description Participant panel research visit day - demonstrations of perceptual phenomena and discussions of potential impact 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Around 60 members of the older adult participant panel of the School of Psychology, University of Aberdeen, attended an annual 2-hour public engagement lunchtime event. Researchers discuss the outcomes of studies that involved panel volunteers or present various engaging and thought-provoking psychology-related demonstrations. While my current PhD student Ms Rozman (BBSRC Eastbio) and my postdoc Dr Reuther (BBSRC) discussed their own research with panel members and demonstrated various visual phenomena which we have prepared for such events (e.g. the Beuchet chair, the hollow face illusion, etc.), I discussed the EPSRC project on visual displays with interested panel members and handed out questionnaires for those who wanted to take part in the qualitative part of the project. Panel members were enthused about their views being given consideration by our project and I handed out more than 30 questionnaires and had conversations with more than 50 older adults. Due to the school holidays, quite a few of them brought their grandchildren to the event, who were enthralled by some of the visual demonstrations, in particular the opportunity to take family photos with the Beuchet chair illusion. This should engender enthusiasm about visual science in both the youngest and the older generation.
Year(s) Of Engagement Activity 2020
 
Description Visual Ageing Workshop 2021 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I organised a half-day workshop on visual ageing, bringing together researchers from different disciplines (psychology, architecture, user experience, display engineering) with an interest in this topic. The workshop began with talks from experts in the field (Prof Leonards, University of Bristol, Dr Allen, University of Nottingham, Dr Akhavan, Faurecia IRYSTec, Prof Platt, Harvard Extension School) which was followed by a general discussion and a networking session. Amongst the 30 attendees, the majority were postgraduates and postdoctoral researchers, mainly from the UK but also including some international participants. The attendees reported that the event benefited both their own research and their future work due to the increased awareness of interdisciplinarity, with some forming potential collaborative links with researchers from other disciplines during the event.
Year(s) Of Engagement Activity 2021
URL https://2021visualageing.wordpress.com/