Research areas

Highlights of Research

Colour Appearance, Colour Vision and Psychophysical Modelling

This research direction investigates how humans perceive colour attributes, including hue, saturation, vividness, blackness, whiteness, brightness and colourfulness. It uses psychophysical experiments to examine observer variability, colour appearance under different viewing conditions, and the validity of existing colour appearance models.

Key topics:

• Colour appearance scales and perceptual dimensions.

• Unique-hue judgements and observer variability.

• Perception of unrelated colours without a conditioning field.

• Achromatic convergence and colour matching.

• Evaluation of CIELAB and CIEDE2000 using cone fundamentals.

Representative publications: Cho et al. (2017), New colour appearance scales for describing Saturation, Vividness, Blackness and Whiteness; Lee and Ou (2026), Characterisation of LCDs using partition scaling and unique hue methods; and the 2026 ACA studies on unrelated-colour perception and CAM15u.

Colour Emotion, Preference, Harmony and Design Applications

This extensive research stream explores how colours and colour combinations evoke emotions, influence preferences, and shape expectations of products and environments. It also investigates how cultural background, age, individual differences, texture, area proportion and product category affect colour responses.

Key topics:

• Models of colour emotion, colour preference and colour harmony.

• Cross-cultural and demographic differences.

• Colour–product associations and consumer expectations.

• Colour harmony in packaging, clothing, fabrics and interior design.

• Quantitative tools for colour selection and design planning.

Representative publications: Ou et al. (2004), the three-part study of colour emotion and preference; Ou and Luo (2006), A colour harmony model for two-colour combinations; Ou et al. (2018), Universal models of colour emotion and colour harmony.

Display Characterisation, Colour Reproduction and Visual Comfort

This direction connects colour science with the practical performance of LCDs, tablets, mobile devices, head-up displays and novel projection systems. It combines physical or colorimetric characterisation with human visual assessments to improve colour reproduction, readability and viewing comfort.

Key topics:

• Psychophysical display characterisation using unique hues and partition scaling.

• Perceived white and colour appearance under different ambient illumination.

• Text–background contrast, readability and visual comfort.

• Observer-specific colour matching and compensation.

• Colour reproduction in augmented-reality glasses and head-mounted displays.

Representative publications: Huang et al. (2018), White appearance of a tablet display under different ambient lighting conditions; Bai et al. (2021), Observer variability study and method to implement observer categories for novel light source projection system; Lee and Ou (2026), Characterisation of LCDs using partition scaling and unique hue methods.

Colour and Visual Perception in Virtual and Augmented Reality

This research stream extends colour appearance and visual perception studies into immersive environments, where display characteristics, illumination, motion and visual context may differ substantially from conventional viewing conditions.

Key topics:

• Colour appearance and reference-white perception in VR.

• Colourimetric characterisation of AR optical systems, including birdbath configurations.

• Effects of display resolution and visual conditions on appearance.

• Visual sharpness and perception in stereoscopic VR headsets.

• Relationships among image chroma, motion, presence and cybersickness.

Representative publications: Ma and Ou (2019), An initial study of colour appearance in virtual reality; Chao and Ou (2024), Colorimetric characterization of augmented reality glasses based on the birdbath optical structure; Lu et al. (2025), A psychophysical investigation of sharpness and visual perception in stereoscopic virtual reality headsets.

Cybersickness, Human Factors and Perceptual Comfort in Immersive Systems

Closely related to the previous direction, this stream focuses specifically on adverse responses to immersive visual experiences and potential mitigation strategies. It investigates the effects of simulated locomotion, constrained head rotation, visual motion and sensory cues on cybersickness and presence.

Key topics:

• Effects of simulated walking and running movements.

• Influence of pitch-, roll- and yaw-constrained rotation.

• Relationships among cybersickness, pupil size and physiological responses.

• Effects of bobbing simulation and step sounds.

• Individual differences and changes in symptoms over repeated sessions.

Representative publications: Zhang and Ou (2025), Simulated bobbing in walking and running in virtual reality; Zhang and Ou (2026), Effects of simulated bobbing and step sounds on cybersickness and presence in virtual reality.

Lighting, Environmental Colour Appearance and Visual Performance

This direction examines how illumination and environmental context shape the perception of colours, objects, spaces and displays. It bridges fundamental appearance research with practical applications in indoor lighting, architectural environments, museums, road lighting and digital reading.

Key topics:

• Colour appearance under indoor, outdoor and complex illumination.

• Neutral-white perception and warm–cool judgements.

• Visual comfort across ambient illuminance levels and age groups.

• Lighting effects on rooms, paintings, faces and interior impressions.

• Visual conspicuity and colour discrimination under challenging conditions.

Representative publications: Ou and Liang (2020), A comparison of colour appearance for surface colours between outdoor and indoor environments; Huang et al. (2017), Effects of age and ambient illuminance on visual comfort for reading on a mobile device; Chang and Ou (2026), A chromaticity-based warm-cool model integrated with the neutral white locus.