Editing Lookup table (section)

=== Lookup tables in image processing ===
{{original research section|date=October 2021}}
[[File:Red Green Blue 16 bit Look up Table Sample.svg|thumb|right|Red (A), Green (B), Blue (C) 16-bit lookup table file sample. (Lines 14 to 65524 not shown)]]

{{blockquote|"Lookup tables (LUTs) are an excellent technique for optimizing the evaluation of functions that are expensive to compute and inexpensive to cache. ... For data requests that fall between the table's samples, an interpolation algorithm can generate reasonable approximations by averaging nearby samples."<ref>[https://developer.nvidia.com/gpugems/gpugems2/part-iii-high-quality-rendering/chapter-24-using-lookup-tables-accelerate-color nvidia gpu gems2 : using-lookup-tables-accelerate-color]</ref>}}

In data analysis applications, such as [[image processing]], a lookup table (LUT) can be used to transform the input data into a more desirable output format.  For example, a grayscale picture of the planet Saturn could be transformed into a color image to emphasize the differences in its rings.

In image processing, lookup tables are often called '''[[3D LUT|LUT]]'''s (or 3DLUT), and give an output value for each of a range of index values. One common LUT, called the ''colormap'' or ''[[palette (computing)|palette]]'', is used to determine the colors and intensity values with which a particular image will be displayed. In [[computed tomography]],  "windowing" refers to a related concept for determining how to display the intensity of measured radiation.