tonemappaukseen

Tonemapping is a process used in computer graphics and image processing to map high dynamic range (HDR) imagery to a lower dynamic range display. Dynamic range refers to the ratio between the brightest and darkest values in an image. Many real-world scenes contain a much wider range of brightness than standard displays like monitors or printed photos can reproduce. Without tonemapping, HDR images displayed on standard devices would appear either too dark in the shadows or too bright in the highlights, losing detail in both areas.

The goal of tonemapping is to compress this wide range of luminance values into a range that a display can handle, while preserving as much detail and perceived realism as possible. Various algorithms exist for tonemapping, each with its own approach to this compression. Some common methods include global tonemapping, which applies a single tone curve to the entire image, and local tonemapping, which adjusts tones based on the characteristics of specific image regions.

Local tonemapping algorithms often analyze the surrounding pixels to determine how to adjust the luminance of a particular pixel, aiming to preserve local contrast and detail. The effectiveness of a tonemapping operator can be subjective, as different algorithms can produce visually distinct results. Ultimately, tonemapping is a crucial step in making high-fidelity visual content accessible and viewable on a wide range of display technologies.