ImageGear Professional for Windows ActiveX
Grayscale Look Up Tables
| ImageGear Professional v18.2 > User Guide > Using ImageGear > Displaying Images > Grayscale Look Up Tables |
The ImageGear API allows you to attach a grayscale look up table (LUT) to IGPage Object and to IGPageDisplay Object. The grayscale look up table can be set for any image, but ImageGear only uses it with grayscale images, and ignores it with the other images. The look up table specifies a transform from the image intensity range to the 8-bit unsigned range. This allows you to display a particular part of an image intensity range, or enhance image contrast.
If both an IGPage Object and corresponding IGPageDisplay Object contain grayscale LUTs, the display LUT overrides the image's LUT. A LUT can be removed from an image and attached to a display, or vice versa.
Storing grayscale a LUT with IGPageDisplay Object allows you to display the same image with different LUTs simultaneously, in different windows.
A grayscale LUT can be used in combination with a RGB LUT. The grayscale LUT is applied first, and then the RGB LUT is applied. In particular, this allows you to apply pseudocoloring after grayscale transformations.
Use IGPageDisplay Object.UpdateGrayscaleLUTFrom Method to create or update a grayscale LUT with the specified LUT. This method copies LUT data to the display settings. Pass NULL (Nothing) to this method to remove a grayscale LUT from the display settings.
Use IGPageDisplay Object.GrayscaleLUTExists Method to check whether IGPageDisplay contains a grayscale LUT.
Use IGPageDisplay Object.GetGrayscaleLUTCopy Method to obtain a copy of the display grayscale LUT.
The ImageGear Medical component provides a set of methods used to build grayscale LUTs according to various DICOM display settings.
An IGLUT Object can have various input and output depths, as well as signed and unsigned output. However, ImageGear applies some restrictions on LUTs that can be attached to IGPage Object or IGPageDisplay Object. Input depth must be 8 or 16, output depth must be 8 and unsigned. 8x8 LUTs can be used for displaying 2...8 bit grayscale images, 16x8 LUTs can be used for displaying 9..16 bit grayscale images.
Working with Grayscale Look-Up Tables
Medical Component Grayscale Look Up Tables