طريقة تحويل الصور الملونه الي صور ابيض واسود

Private Sub btnOpenColorImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpenColorImage.Click

Dim dlg As OpenFileDialog = New OpenFileDialog()
Dim imagFilter As String = "Image files (*.jpg,*.jpeg,*.bmp,*.gif,*.png)|*.BMP;*.PNG;*.JPG;*.JPEG;*.GIF"

dlg.Filter = imagFilter

dlg.RestoreDirectory = True


If dlg.ShowDialog() = DialogResult.OK Then
Dim img As Image = Image.FromFile(dlg.FileName)

PictureBox1.Image = img.GetThumbnailImage(PictureBox1.Width, PictureBox1.Height, Nothing, Nothing)


End If
End Sub

Private Sub btnConvertToGray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConvertToGray.Click

If PictureBox1.Image Is Nothing Then
Dim msgString As String = "Load the Colored Image"
Dim msgCaption As String = "Error"

MessageBox.Show(msgString, msgCaption, MessageBoxButtons.OK, MessageBoxIcon.Warning)

Else
Dim grayImage As Image = PictureBox1.Image
Dim bm As Bitmap = New Bitmap(grayImage.Width, grayImage.Height)
Dim g As Graphics = Graphics.FromImage(bm)
Dim cm As System.Drawing.Imaging.ColorMatrix = New System.Drawing.Imaging.ColorMatrix(New Single()() _
{New Single() {0.3, 0.3, 0.3, 0, 0}, _
New Single() {0.59, 0.59, 0.59, 0, 0}, _
New Single() {0.11, 0.11, 0.11, 0, 0}, _
New Single() {0, 0, 0, 1, 0}, _
New Single() {0, 0, 0, 0, 1}})

Dim ia As System.Drawing.Imaging.ImageAttributes = New System.Drawing.Imaging.ImageAttributes()
ia.SetColorMatrix(cm)
g.DrawImage(grayImage, New Rectangle(0, 0, grayImage.Width, _
grayImage.Height), 0, 0, grayImage.Width, _
grayImage.Height, GraphicsUnit.Pixel, ia)
g.Dispose()
PictureBox2.Image = bm.GetThumbnailImage(PictureBox2.Width, PictureBox2.Height, Nothing, Nothing)

End If

End Sub

Private Sub btnSaveGrayImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveGrayImage.Click

Dim SaveFileDialog1 As New SaveFileDialog()
SaveFileDialog1.Filter = "Image files (*.BMP, *.JPG, *.GIF)|*.bmp;*.jpg;*.gif"

If SaveFileDialog1.ShowDialog() = DialogResult.OK Then
If Not PictureBox1.Image Is Nothing Then
PictureBox2.Image.Save(SaveFileDialog1.FileName)
End If

End If
End Sub

End Class

Public Class Form1

Dim cm As ColorMatrix = 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() {0, 0, 0, 0, 1}})