# Compute Map Parameters

Display the Compute Map Parameters section with the button in the top right corner, left from the image display.

With the PixelMapComputeParams, you can fine-tune the reference points that are generated when b is called (when the user clicks on the compute button or when the Auto Compute Reference Points is enabled).

Parameter | Description
--- | ---
Algorithm | Specifies the algorithm used to compute the input range that will be mapped to the output range. MinMax: Uses the minimum and maximum values in the histogram statistics of the input image to fill the output range. Tails: Uses the low tail and high tail in the histogram statistics of the input image to fill the output range. MeanStdDev: Uses the mean minus a multiple of the standard deviation and the mean plus a (possibly different) multiple of the standard deviation to fill the output range. TypeRange: Use the minimum and maximum values of the range of the input type (e.g. 0 and 65536 for 16-bit input images) to fill the output range. Note that the "proper" mapping of, e.g., the full 16-bit range to the full 8-bit range is a shift by 8 bits (or, equivalently, a division by 256), which implies that the correct mapping is from 65536 to 256, rather than from 65535 to 255.
Low Tail Fraction | The Low tail fraction is in the range [0, 1]. Used only if the Algorithm is Tails. The Low Tail Fraction and the High Tail Fraction when added must be less or equal to 1. As one property increases the other will decrease.
High Tail Fraction | The High tail fraction is in the range [0, 1]. Used only if the Algorithm is Tails. The Low Tail Fraction and the High Tail Fraction when added must be less or equal to 1. As one property increases the other will decrease.
Low Pad Faction | The fraction of the initially-computed input range added to the initially-computed value of first map value. This value is typically negative.
High Pad Faction | The fraction of the initially-computed input range added to the initially-computed value of second map value. This value is typically positive.
Output Range | Specifies the output range used in the mapping.
Max Range Multiplier | Used to convert input pixels to output pixels, where the maximum pixel value is clipped to the maximum value allowed by the image type. For example, if the output image is a 16-bit grey scale image, with an encoding of 10, the upper limit of the range cannot be greater than 1024. This setting is particularly useful when mapping from an Image16Range image to an Image16Grey image, which allows the full 16-bit range image to be used, instead of just a portion of the image. Note: Only used when Auto Compute Reference Points is enabled.
Output1 Fraction | Specifies the first output pixel value used in the mapping. Used only if OutputRange is SpecifiedRelative. Range value is [0-1].
Output2 Fraction | Specifies the second output pixel value used in the mapping. Used only if OutputRange is SpecifiedRelative. Range value is [0-1].