Dr Pepper lecturing

MEETINGS FOR 2015-2016
Awardees of the WDW awards, 2015

Wednesday 04 November 2015
City University, Room R101, Franklin Building, 124 Goswell Road, EC1V 7DP

Details of these awards may be seen here.
A condition of each Award is that the holder shall describe the work they presented to
the meeting/event that they were funded to attend.

The Colour Group is grateful to CAMBRIDGE RESEARCH SYSTEMS LTD for sponsoring the CRS Award which was made to
Tushar Chauhan who will present his work to the Group at a later date..


14:00-14:15 W. D. Wright Travel Award Matthew Cranwell
Institute of Neuroscience, Newcastle University.
Dissociation of chromatic discrimination ability in developmental disorders: Autism Spectrum Disorder and Williams Syndrome
14:15-14:30 Colour Mentor Vien Cheung
School of Design, University of Leeds.
Workflows in digital colour systems
14:30-14:45 W. D. Wright Travel Award Mengmeng Wang
School of Design, University of Leeds.
Investigation of uncertainty of skin colour measurements
14:45-15:00 General Discussion  
15:00-15:30 TEA
15:30-15:45 Colour Mentor Marina Bloj
Bradford School of Optometry and Vision Sciences
What the #the dress taught us
15:45-16:00 W. D. Wright Travel Award Joseph Hickey
Optometry & Vision Science, City University.
Chromatic sensitivity and visual search in air traffic control
16:00-16:15 W. D. Wright Travel Award John Maule
Department of Psychology, University of Sussex.
Accurate estimation of the mean hue of rapidly presented multi-hue ensembles
16:15-16:30 General Discussion and Concluding remarks

Room R101, Franklin Building, 124 Goswell Road, EC1V 7DP
This is about five minutes walk south of the main campus. For map and pictures, see the bottom of this link.

Open to all, gratis.

Matthew Cranwell

Mathew Cranwell Dissociations of chromatic discrimination ability in developmental disorders:  Autism Spectrum Disorder and Williams Syndrome.

Introduction: Atypical visual processing has been reported in both Autism Spectrum Disorder (ASD) and Williams Syndrome (WS), two developmental conditions which typically have contrasting social profiles despite overlapping socio-communicative deficits. Here we dissociate visual processing deficits between the two syndromes by using colour perception to examine ventral stream function, which underlies key aspects of socio-communicative ability.
Methods:  Children (7-18 years) with ASD (N=15) or WS (N=26) and mental-age equivalent typically developing (TD) children (6-9 years) (matching Ns)  each completed two chromatic discrimination tasks: (1) the Farnsworth-Munsell 100-Hue Test (FM100), a manual cap-sorting task requiring the ordering of hues at equal lightness and saturation to form a smooth chromatic gradient, and (2) a computer-based threshold discrimination test, which assessed discrimination along cone-opponent (“red-green”, “blue-yellow”) and luminance cardinal axes via a staircase procedure, in which participants reported on each trial the direction of a briefly-flashed arrow.
Results:  In FM100 performance, there were no significant differences between the ASD and WS relative to TD groups. Yet performance was significantly related to non-verbal IQ. For the threshold task, a significant main effect of group was found between TD and ASD, driven by significantly poorer “blue-yellow” discrimination in ASD.  Between the WS and TD groups there were no significant differences in performance.  Crucially, there were no significant correlations between threshold task performance and any IQ measure.
Conclusion:  Chromatic discrimination is reduced in ASD but not in WS, relative to TD, but this dissociation is not revealed by a task which confounds visual discrimination ability with non-verbal ability.

Vien Cheung
Workflows in digital colour systems

Colour displays are now affordable and enjoyed by consumers at work, at home, on mobile displays and in cinemas. Consumers often take it for granted that there is good colour fidelity as images are transferred between different devices. For example, a red object in an image appears to be approximately the same red when the image is displayed on different computer displays, when it is printed, and when it is viewed on a mobile phone. This colour fidelity is not easy to achieve. Different devices use very different technology to display colour images. Colour management is required to compensate for differences between the technologies. This level of colour fidelity is probably sufficient to satisfy about 90% or more of consumers for whom colour is not a critical issue; but it does not, for example, generally account for changes in settings for a device. For professionals working in industries where colour is a major concern (e.g. design, retailing) a higher level of colour management is often required.

Mengmeng Wang

wangInvestigation of uncertainty of skin colour measurements

Skin colour is widely needed by cosmetic industries and hospitals for developing makeups and diagnoses skin disease. Different from the other materials, the human skin is a multilayer soft tissue with colour unevenly distributed. Therefore, the pressures, measurement area sizes and different instruments can affect the measurement results of the skin colour. CIE colorimetry has been widely used for more than 30 years to provide objective measurements for human skin colour. Tele-spectroradiometers (TSRs), spectrophotometers (SPs) are two widely-used skin colour measurement. Although, large amounts of work on human skin colour measurements were based on these two instruments, the research of the measurement uncertainty by using these two instruments to measure human skin colour were limited. A research project was set up between the University of Liverpool and the University of Leeds to measure skin colours for different ethnicities and using different instruments. About 200 people's 10 locations were measured by four different instruments, including a SP and a TSR. This study is a pilot study of this research project, which aimed to investigate the uncertainty of using a SP and a TSR to determine their short-term repeatability under different settings and consistency between these two instruments. Measurement methods of using these two instruments to measure 200 people were based on this study.

Marina Bloj

The Dress What the #the dress taught us

In February this year social media provided colour scientists and colour aficionados a great example of the perceptual ambiguities of our colour vision: the infamous 'blue/black or is it white/gold' dress. In my presentation I will not only talk about some experiments I was involved in (Gegenfurtner, K.R., Bloj, M. & Toscani, M., 2015. The many colours of the dress. Current Biology, 25, R543-R544) but also use this opportunity to comment on the relationship between scientists, media and the general public.

Joseph Hickey
Chromatic sensitivity and visual search in air traffic control

Visual search is used to deploy attention at relevant points in the visual field (Wolfe & Horowitz, 2004). Colour has been well established as an object feature that can pre-attentively guide visual search, if adequately salient, and this is dependent on the strength of the chromatic signal and the heterogeneity of the coloured object with its surround (Nagy & Sanchez, 1990; Bauer et al, 1996).
In air traffic control, colour coding is used to direct the user’s attention to the progress and condition of relevant aircraft, and as such many aviation authorities impose normal trichromacy for air traffic controllers. However, colour vision tests employed to screen new applicants have been shown to pass some colour deficient applicants (Rodriguez-Carmona et al, 2012). No incidents have been reported involving operational failure relating to colour vision loss, and this indicates that the task can be performed safely by some anomalous trichromats.
In this study the chromatic discrimination thresholds of normal trichromats, as well as deutan and protan subjects (anomalous trichromats and dichromats), are related to a set of visual search tasks involving physiologically unique hues over a range of chromatic saturations, that are designed to replicate the use of colour coding in display screens.
Results illustrate the effect of chromatic sensitivity on response times; some minimally-deficient subjects can perform within the normal range under certain conditions. The responses of all subject groups appear to be significantly affected by the polarity of luminance contrast of coloured targets, with respect to the background field. nces

Wolfe, J. M., & Horowitz, T. S. (2004). What attributes guide the deployment of visual attention and how do they do it? Nature Reviews Neuroscience, 5(6), 495-501.
Nagy, A. L., & Sanchez, R. R. (1990). Critical color differences determined with a visual search task. JOSA A, 7(7), 1209-1217.
Bauer, B., Jolicoeur, P., & Cowan, W. B. (1996). Visual search for colour targets that are or are not linearly separable from distractors. Vision research, 36(10), 1439-1466.
Rodriguez-Carmona, M., O’Neill-Biba, M., Barbur, J. L. (2012). Assessing the severity of color vision loss with implications for aviation and other occupational environments. Aviat. Space Environ. Med., 83(1), 19-29.

John Maule
Accurate estimation of the mean hue of rapidly presented multi-hue ensembles

Colour can be important to understanding the gist of a scene, but can humans extract the gist of the colours of objects they see for a very short time? We have previously shown that observers can select, when given a two-alternative forced-choice, the average hue of a multi-hue ensemble presented for 500ms (Maule, Witzel & Franklin, 2014). This study indicated the conditions under which observers were better-than-chance at selecting means, but did not provide a measure of the accuracy of mean encoding. Here, we investigate the accuracy of mean encoding and the underlying mechanisms of rapid averaging. Following brief (500ms) presentation of heterogeneous (multi-hue) and homogeneous (single-hue) ensembles, observers (N = 15) adjusted the hue of an array until they felt it represented the mean hue of the ensemble just seen. Settings were compared to the expected mean hue, based on a JND-scaled hue circle, to identify the accuracy of mean representation. Results indicated that the observers converged extremely closely on the expected mean hue for both heterogeneous and homogeneous ensembles. However, absolute error from the expected mean was greater for heterogeneous than homogeneous ensembles, by approximately half a JND. An ideal observer simulation showed that these average settings could have been obtained using a sub-sampling mechanism. This contributes to the debate about whether the full ensemble is included in the average estimate or whether perceptual averaging is due to sub-sampling of relatively few items. The findings have implications for the perception of variegated scenes, heterogeneous sets and colour memory.

DATE 28 October 2015