Visual basic Image Processing Brightness Adjustment source Code

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These VB Functions Allows the Brightness of a image to be toned down or up. Try both to see which meet your needs. You can use the Brightness Adjustment function as a inline function to control the bightness of both still images and Videos.


	Brightness	Constrast

'Brightness ColorMatrix
Public Function AdjBrightness(ByVal MyImage As Image, ByVal brt As Single) As Image
   brt = brt / 10

Dim cm As ColorMatrix
      cm = New ColorMatrix(New Single()() { _
      New Single() {brt, 0.0, 0.0, 0.0, 0.0}, _
      New Single() {0.0, brt, 0.0, 0.0, 0.0}, _
      New Single() {0.0, 0.0, brt, 0.0, 0.0}, _
      New Single() {0.0, 0.0, 0.0, 1.0, 0.0}, _
      New Single() {0.0, 0.0, 0.0, 0.0, 1.0}})

Return draw_adjusted_image(MyImage, cm)
End Function
'Contrast ColorMatrix
Function contrast(ByVal image As Image, ByVal value As Single) As Image
   Dim sb As Single
   If value = 0 Then
      Exit Function
   End If
   sb = value / 255.0F
   m_StartingImage = image
   Dim cm As ColorMatrix
    cm = New ColorMatrix(New Single()() _
    {New Single() {1, 0, 0, 0, 0}, _
     New Single() {0, 1, 0, 0, 0}, _
     New Single() {0, 0, 1, 0, 0}, _
     New Single() {0, 0, 0, 1, 0}, _
     New Single() {sb, sb, sb, 1, 1}})

Return draw_adjusted_image(m_StartingImage , cm)
End Function

'Helper Function
Private Function draw_adjusted_image(ByVal MyImage As Image, ByVal cm As ColorMatrix) As Image
   Dim bm As Bitmap

Try
      Dim image_attr As New ImageAttributes
      Dim rect As Rectangle = Rectangle.Round(MyImage.GetBounds(GraphicsUnit.Pixel))<br />
      Dim width As Integer = MyImage.Width
      Dim height As Integer = MyImage.Height
      Dim gr As Graphics
      bm = New Bitmap(width, height)
      gr = Graphics.FromImage(bm)
      image_attr.SetColorMatrix(cm)
      gr.DrawImage(MyImage, rect, 0, 0, width, height, GraphicsUnit.Pixel,image_attr)
      working_Image = bm
      Return bm
      gr.Dispose()
      image_attr.Dispose()
      image_attr = Nothing
   Catch ex As Exception

End Try
   Return bm
End Function

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Visual basic Code Sample Image brightness and Constrast