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The Limits of Natural and Artificial Compensation in Abnormal Color Vision
About 6% of males are classified as anomalous trichromats because in matching red and green mixtures to a yellow reference, their red-green ratios are outside the limits for normal trichromats. This is known due to cone spectral sensitivity shifts caused by hybrid gene sequences coding cone opsins. Several studies show, however, that predicted perceptual loss from increased cone spectral overlap is not as severe as expected, implying a compensatory mechanism for the information loss. Compensation is expected if neural systems adjust to the range of encoded input to exploit the full range of neural responses.

In this webinar hosted by the Color Technical Group, Kenneth Knoblauch will present evidence for such compensation using a psychophysical approach to estimate luminance and chromatic contrast response functions. Anomalous observers require higher chromatic contrasts at the threshold, but contrast response rises more steeply than normal observers, indicative of contrast gain enhancement. Noise in contrast encoding limits the full benefits of such compensation and induces a dependence between contrast gain and maximal response. Interestingly, long-term usage of notch filters designed to enhance chromatic contrast for anomalous observers enhances contrast appearance without the filters. This is likely explained by the same gain-noise interaction described above but working in the opposite sense. The results support that optimal vision depends on an exquisite balance between gain and noise.

Subject Matter Level: Intermediate - Assumes basic knowledge of the topic

What You Will Learn:
• A rigorous method for estimating a scale describing appearance along a physical dimension
• Factors that constrain the perception of contrast in normal and anomalous vision


Who Should Attend:
• Individuals interested in color vision, including students, researchers, clinicians, design engineers
• Individuals interested in how color anomalies affect perception

Dec 7, 2022 11:00 AM in Eastern Time (US and Canada)

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Speakers

Kenneth Knoblauch
@Stem Cell and Brain Research Institute France
Kenneth Knoblauch is a research director at the Stem Cell and Brain Research Institute at INSERM in France and holds a part-time professor position at the University of Southeast Norway. Knoblauch is interested in the neural basis of perception and uses methods from psychophysics, functional imaging and modeling neural mechanisms and cortical connectivity. Knoblauch has recently worked on the development of quantitative tools to measure visual appearance and used these to characterize a color filling-in phenomenon, infant color perception, contrast response in normal and anomalous color vision and multi-modal integration in gender perception.