Lutetype

Lutetype is a term used to describe the data type and layout of a look-up table (LUT) in computing. It denotes how input values are mapped to output values by indexing into an array, and it encompasses the element data type, dimensionality, and interpretation of stored values.

A LUT is typically organized as a one-dimensional, two-dimensional, or three-dimensional array. The lutetype defines the storage details, including the number of entries, the number of channels per entry, and the numerical type used for the stored values (for example, 8-bit unsigned integers, 16-bit integers, or floating-point numbers). It also influences how input coordinates are translated into array indices and how interpolated values are produced when inputs do not exactly match a LUT entry.

Common LUT categories include 1D LUTs for simple transfer functions or gamma corrections, 2D LUTs for basic color transformations, and 3D LUTs for complex color grading. Typical sizes vary by category, such as 1D LUTs with a few dozen to a couple of hundred entries, and 3D LUTs that form cubic grids like 17x17x17 or 33x33x33. The chosen lutetype affects precision, memory usage, and performance of sampling operations in rendering or image processing pipelines.

In practice, lutetype guides how software allocates storage, performs sampling, and applies interpolation (nearest, linear, trilinear, or more advanced methods). It is a key consideration in color management, shader programming, and image processing frameworks, where consistent interpretation of LUT data ensures predictable color transformation and lookup results.

See also: lookup table, 1D LUT, 2D LUT, 3D LUT, color management.