Lookup tables are thus used by mathematics coprocessors in computer systems. When the program requires the sine of a value, it can use the lookup table to retrieve the closest sine value from a memory address, and may also interpolate to the sine of the desired value, instead of calculating by mathematical formula. The same application can finish much sooner when it first precalculates the sine of a number of values, for example for each whole number of degrees (The table can be defined as static variables at compile time, reducing repeated run time costs). Calculating trigonometric functions can substantially slow a computing application. For example, a grayscale picture of the planet Saturn will be transformed into a color image to emphasize the differences in its rings.Ī classic example of reducing run-time computations using lookup tables is to obtain the result of a trigonometry calculation, such as the sine of a value. In data analysis applications, such as image processing, a lookup table (LUT) is used to transform the input data into a more desirable output format. For data requests that fall between the table's samples, an interpolation algorithm can generate reasonable approximations by averaging nearby samples." "Lookup tables (LUTs) are an excellent technique for optimizing the evaluation of functions that are expensive to compute and inexpensive to cache. Red (A), Green (B), Blue (C) 16-bit lookup table file sample. The process is termed as "direct addressing" and LUTs differ from hash tables in a way that, to retrieve a value v Lookup tables in image processing In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation. Array that replaces runtime computation with a simpler array indexing operation
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