private void buttonNext_Click_1(object sender, EventArgs e)
 {
     if ((textBoxT.Text != String.Empty) && (textBoxT.Text != "0"))
     {
         t_ = (Convert.ToInt32(textBoxT.Text));
         ImageForm i = new ImageForm();
         i.MdiParent = this.MdiParent;
         i.DifferencePart2(bmpo_, bitmapToDifference_, t_);
         i.Show();
     }
 }