Color Constancy Demonstration

Color Constancy

The phenomenon where the perceived color of an object remains relatively constant under varying illumination conditions.

Rubik's Cube Example

Demonstration of color constancy using two Rubik's cubes under yellow and blue light. Despite different lighting, observers can still identify the red tiles.

Chromatic Adaptation

The process by which the eyes adapt to the light source over time, affecting the sensitivity of photoreceptors to different wavelengths.

Selective Adaptation Experiment

Practical exercise where participants adapt their eyes to a red stimulus, demonstrating chromatic adaptation.

Green Paper Experiment

Experiment showing how chromatic adaptation works using a green piece of paper under different lighting conditions.

The Dress Phenomenon

The viral image of a dress seen as either black and blue or white and gold, illustrating color constancy and personal adaptation.

Surrounding Colors

The context of surrounding colors enhances color constancy, making an object's color perception more consistent.

Memory Color

Familiarity with an object's usual color affects perception, as demonstrated by an experiment where a grayscale banana is still perceived as slightly yellow.

Lightness Constancy

The perception of achromatic colors (black, white, and gray) remaining constant despite changes in illumination.

Chessboard Example

Demonstration of lightness constancy using a chessboard under different lighting conditions, showing that perceived lightness remains constant.

Reflectance and Illumination Edges

Differences in perceived lightness are due to either changes in material (reflectance edges) or changes in illumination (illumination edges).

Shadow Example

Perception of shadows, influenced by the penumbra, helps distinguish between illumination changes and material changes.

Color as a Perceptual Phenomenon

Color is a perceptual construct created by the brain, not an inherent property of light waves.

Perception and Reality

The lecture concludes by emphasizing that color perception aids in object identification and environmental interaction.

Phenomenon of Color Constancy

The lecture explores the phenomenon of color constancy and how our visual system maintains stable color perception despite varying environmental conditions.

Influence of Physiological Adaptations

The lecture discusses how physiological adaptations, such as chromatic adaptation, contribute to color constancy.

Influence of Cognitive Factors

The lecture highlights the role of cognitive factors, such as surrounding colors and memory color, in color constancy.

Examples of Color Constancy

The lecture provides examples of color constancy phenomena, including the Rubik's Cube, the Green Paper Experiment, and the Dress Phenomenon.

Mechanisms of Color Constancy

The lecture explains the mechanisms behind color constancy, including chromatic adaptation and contextual influences.

Lightness Constancy and Achromatic Colors

The lecture explores lightness constancy and how it relates to the perception of achromatic colors.

Edges and Shadows in Color Perception

The lecture discusses the role of edges and shadows in color perception, specifically in distinguishing between illumination changes and material changes.