H. Presentation LUT

The Presentation LUT transforms the polarity pixel values into Presentation Values (P-Values), which are meaningful for display of the images. P-Values are approximately related to human perceptual response. They are intended to facilitate consistent display with common input for both hardcopy and softcopy display devices and be independent of the specific class or characteristics of the display device. It is used to realize image display tailored for specific modalities, applications, and user preferences

In the Print Management Service Class, the Presentation LUT is part of the Presentation LUT IOD.

Hardcopy devices convert P-Values into optical density for printing. This conversion depends on desired image D-max and D-min. It also depends on expected viewing conditions such as lightbox intensity for transparency films. The conversion to printed density is specified in the Presentation LUT SOP Class.

If the modality desires to natively specify P-Values as its output, it can negotiate for support of the Presentation LUT, but specify a LUT that is an identity function. The identity function informs the display device that no further translation is necessary.

Note: Performing this translation in the printer prevents potential loss of precision (detail) that would occur if this translation were to be performed on many of the existing 8-bit modalities.