gammacompression

Gammacompression is a nonlinear signal processing operation that reduces the dynamic range of a signal by applying a gamma-based mapping. The transformation is typically defined on normalized input values x in the interval [0,1] and produces an output y = x^gamma, where gamma is a positive real constant chosen to control the degree and direction of compression.

In practice, gamma greater than 1 tends to compress high-intensity values while expanding lower ones, helping to preserve details in the highlights; gamma less than 1 does the opposite, improving visibility in shadows. To avoid artifacts at the endpoints, implementations often include a small offset or a piecewise-linear region near zero or near one and may use adaptive gamma that depends on local image content.

Applications of gammacompression include image and video pipelines to reduce dynamic range before quantization or display, in HDR tone-mapping as a pre- or post-processing step, and in data visualization where perceptual uniformity is desired. In audio and sensor data, gamma-based compression can be used to squash large amplitude variations and fit data into a fixed bit depth or display scale.

Relation to related concepts: Gammacompression is closely related to gamma encoding/decoding in imaging systems. It is often contrasted with logarithmic or piecewise companding approaches and may be implemented via lookup tables, polynomial approximations, or hardware nonlinearities.

History: The concept originated from gamma correction practices in CRT displays and has since been adapted for digital imaging and display pipelines.