ImageGear .NET - Updated
Consistent Display of Images
User Guide > How to Work with... > DICOM > Presentation State > Consistent Display of Images

The DICOM standard introduces the Standardized Display System. A Standardized Display System may be a printer, a monitor, or some other display device which has been calibrated according to the Grayscale Standard Display Function. The main feature of such display system is that throughout its display range, equal differences in digital input values correspond to visually equal differences in luminosity. Two Standardized Display Systems will always show the same detail in an image, even if their physical characteristics are different.

The values that can be used as input to a Standardized Display System are called "Presentation Values" ("P-Values"). To map image pixel intensities into P-Values, Presentation Look Up Table ("P-LUT") is used. It is applied after Modality and VOI LUTs.

Presentation LUT is stored in a Presentation State DataSet.

If a display device is not physically calibrated to comply with the Standard Display Function, but its characteristic curve (a table that lists luminosities for each digital input value) is known, it can be calibrated at the software level. In that case, P-Values shall be used as input to a Standard Display LUT, which will map them to the device's input values according to Standard Display Function. Thus, a non-standardized device, together with its Standard Display LUT, can be considered as Standardized Display System.

The ImageGear.Formats.DICOM namespace allows you to build a Standard Display LUT from a device's Characteristic Curve.

ImageGear uses all available LUTs (Modality LUT, VOI LUT, Presentation LUT, and Standard Display LUT), to build the Summary LUT that maps image pixel values into display input values.

Presentation LUT and Standard Display LUT, as well as Modality and VOI LUTs are stored in the ImGearDICOMDisplaySettings Class. It can be attached to any ImGearRasterPage Class