GetLookupTable Method

Summary

Gets the 8-bit lookup table (LUT) of this RasterImage.

Syntax

Objective-C

C++/CLI

Java

Python

public RasterColor[] GetLookupTable()

@property (nonatomic, strong, readonly, nullable) NSArray<LTRasterColor *> *lookupTable

public RasterColor[] getLookupTable(); 
public void setLookupTable( 
   RasterColor[] rasterColor[ 
);

public: 
array<RasterColor>^ GetLookupTable();

def GetLookupTable(self):

Return Value

An array of RasterColor structures which represent the lookup table (LUT) of this RasterImage.

Remarks

The lookup table (LUT) is used when the value of UseLookupTable is set to true.

The 8-bit and 16-bit lookup tables are synchronized, so when you change one, the other is changed as well The 16-bit lookup table (GetLookupTable16) has more precision so it is recommended you use the 16-bit LUT instead of the 8-bit LUT.

LUT is also used for displaying extended Palette color image such as bit stored is 16-bit and LUT contains color value. This is typical of Ultra Sound image.

For more information, refer to Grayscale Images.

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using Leadtools.Svg; 
 
 
public void SetLookupTable() 
{ 
   DicomEngine.Startup(); 
 
   // Create a RasterCodecs class for saving out images 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // Load a dataset 
   DicomDataSet ds = new DicomDataSet(); 
   ds.Load(Path.Combine(LEAD_VARS.ImagesDir, "DICOM", "image3.dcm"), DicomDataSetLoadFlags.None); 
 
   // Get the image but do NOT auto-apply any of the LUTs 
   DicomElement element = ds.FindFirstElement(null, DicomTag.PixelData, true); 
   RasterImage image = ds.GetImage(element, 0, 16, RasterByteOrder.Gray, DicomGetImageFlags.None); 
   image.UseLookupTable = true; 
 
   // Save out the image without any LUTs applied.  It should be black 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "BeforeSetLookupTable.bmp"), RasterImageFormat.Bmp, 8); 
 
   // Create a LUT 
   RasterColor[] lut = new RasterColor[(int)Math.Pow(2, 16)]; 
 
   // Get the Minimum and Maximum values so we can calculate appropriate LUT values. 
   MinMaxValuesCommand cmdMinMax = new MinMaxValuesCommand(); 
   cmdMinMax.Run(image); 
   int maxVal = cmdMinMax.MaximumValue; 
   int minVal = cmdMinMax.MinimumValue; 
 
   for (int i = 0; i < lut.Length; i++) 
   { 
      lut[i].R = Convert.ToByte(Math.Min(255, ((i - minVal) * 255 / (maxVal - minVal)))); 
      lut[i].G = lut[i].R; 
      lut[i].B = lut[i].R; 
   } 
 
   // Set the new lookup table 
   image.SetLookupTable(lut); 
 
   // Save out the image with the LUT applied.  It should look normal 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "DICOM", "AfterSetLookupTable.bmp"), RasterImageFormat.Bmp, 8); 
 
   DicomEngine.Shutdown(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

Leadtools.Drawing.RasterPaintCallbacks

Implementing custom paint

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Help Version 23.0.2024.2.29

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Leadtools.ImageProcessing Namespace

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