Luminantiecontras

Luminantiecontras is a term used in discussions of visual perception and image processing to denote a perceptual measure of luminance contrast that incorporates human luminance adaptation. The term blends the Dutch words luminantie (luminance) and contras (contrast).

Definition and concept: Luminantiecontras describes a perceptual metric that combines luminance difference with local adaptation to reflect how the human visual system perceives contrast across changing brightness. For adjacent regions with luminances L1 and L2, perceived contrast is modeled as a function C = f(|L1−L2|, A), where A is the local adaptation luminance. In practice, luminantiecontras is often normalized to a 0–1 scale to facilitate comparison across images.

Applications: It is used in display calibration, HDR tone mapping, image enhancement, and computer vision tasks that benefit from contrast-aware processing, such as edge preservation and region segmentation under nonuniform lighting.

Computation and measurement: The calculation typically involves constructing a local luminance map, estimating adaptation A (often via a local average or percentile), computing local luminance differences, applying a perceptual weighting, and normalizing to a standard range.

Relation to other metrics: Luminantiecontras relates to Michelson contrast, RMS contrast, and Weber contrast but emphasizes adaptation effects. It is complementary to structure- or gradient-based measures used in modern imaging pipelines.

Limitations and critique: As a conceptual metric, its results depend on assumed viewing conditions, color content, and the chosen adaptation model. There is no universal standard for f or A, which can limit cross-study comparability.

See also: Luminance, Contrast (vision), Local contrast, HDR imaging, Perceptual metrics.