Tonemappingi

Tonemappingi is not a standard term in imaging theory. It is likely a misspelling or seldom-used variant of tonemapping. Tonemapping itself refers to the process of converting high dynamic range HDR images into a displayable format for standard dynamic range devices, while preserving perceptual brightness and detail.

Tonemapping aims to compress wide luminance ranges so that image content remains visible across shadows, midtones, and highlights. There are two broad classes of operators: global and local. Global tonemapping applies a single curve to all pixels, producing consistent compression but sometimes reducing local contrast. Local tonemapping adjusts the curve differently across image regions to preserve edges and local detail, which can better convey depth but may introduce artifacts if not tuned carefully.

Common examples of global operators include the Reinhard operator and its variants, which provide intuitive appearance by compressing brightness with a simple function. Local operators include methods by Durand and MacDonald, Fattal et al., and Mantiuk et al., which emphasize preserving local contrast and texture. The choice of operator depends on the scene, display characteristics, and artistic intent. Practical workflows typically involve computing a luminance channel, applying a tone-mapping curve, re-saturating color channels, and enforcing color gamut and clipping constraints, followed by gamma correction to match the target display response.

Tonemapping is widely used in photography post-processing, computer graphics rendering, and visual effects to present HDR content on standard displays. Evaluation combines subjective viewing with objective metrics such as TMQI and HDR-VDP-2. When encountered, tonemappingi is usually a misspelling or informal reference to the standard tonemapping process.