WindowLevelFillLookupTable Method

'Declaration
 
Public Shared Sub WindowLevelFillLookupTable( _
   ByVal lookupTable() As RasterColor, _
   ByVal startColor As RasterColor, _
   ByVal endColor As RasterColor, _
   ByVal low As Integer, _
   ByVal high As Integer, _
   ByVal lowBit As Integer, _
   ByVal highBit As Integer, _
   ByVal minValue As Integer, _
   ByVal maxValue As Integer, _
   ByVal factor As Integer, _
   ByVal flags As RasterPaletteWindowLevelFlags _
) 

Public Sub WindowLevelFillLookupTableExample()
      Dim codecs As RasterCodecs = New RasterCodecs()

      codecs.ThrowExceptionsOnInvalidImages = True

      Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")
      Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1_WindowLevel.tif")

      ' Load an image as 8 bits/pixel
      Dim image As RasterImage = codecs.Load(srcFileName, 8, CodecsLoadByteOrder.Rgb, 1, 1)

      ' change the image to be 16-bit grayscale
      Dim grayscaleCmd As GrayscaleCommand = New GrayscaleCommand(16)
      grayscaleCmd.Run(image)

      ' get the lookup table size
      Dim lookupTableSize As Integer = 1 << (image.HighBit - image.LowBit + 1)

      ' get low/hight bits and minimum/maximum value of this grayscale image
      Dim minMaxBitsCmd As MinMaxBitsCommand = New MinMaxBitsCommand()
      minMaxBitsCmd.Run(image)

      Dim lowBit As Integer = minMaxBitsCmd.MinimumBit
      Dim highBit As Integer = minMaxBitsCmd.MaximumBit

      Dim minMaxValuesCmd As MinMaxValuesCommand = New MinMaxValuesCommand()
      minMaxValuesCmd.Run(image)
      Dim minVal As Integer = minMaxValuesCmd.MinimumValue
      Dim maxVal As Integer = minMaxValuesCmd.MaximumValue

      ' create the lookup table
      Dim lookupTable As RasterColor() = New RasterColor(lookupTableSize - 1) {}

      Dim flags As RasterPaletteWindowLevelFlags = RasterPaletteWindowLevelFlags.Inside Or RasterPaletteWindowLevelFlags.Linear

      If image.Signed Then
         flags = flags Or RasterPaletteWindowLevelFlags.Signed
      End If

      ' initialize the fill lookup table parameters
      Dim startColor As RasterColor = RasterColor.FromKnownColor(RasterKnownColor.Red)
      Dim endColor As RasterColor = RasterColor.FromKnownColor(RasterKnownColor.Blue)

      Dim low As Integer = 23000
      Dim high As Integer = 45000
      Dim factor As Integer = 10

      ' fill the lookup table
      RasterPalette.WindowLevelFillLookupTable(lookupTable, startColor, endColor, low, high, lowBit, highBit, minVal, maxVal, factor, flags)

      ' now do window level on the image
      image.WindowLevel(lowBit, highBit, lookupTable, RasterWindowLevelMode.PaintAndProcessing)

      ' save it back on disk
      codecs.Save(image, destFileName, RasterImageFormat.Tif, 16)

      ' Clean up
      image.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class