private void contagemToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (img == null) // verify if the image is already opened
            {
                return;
            }
            Cursor = Cursors.WaitCursor; // clock cursor

            //copy Undo Image
            imgUndo = img.Copy();

            MIplImage s     = imgUndo.MIplImage;
            int       width = s.width;


            Projection_X form = new Projection_X(ImageClass.Projection_X(imgUndo), width);

            form.ShowDialog();


            ImageViewer.Image = img.Bitmap;
            ImageViewer.Refresh();    // refresh image on the screen

            Cursor = Cursors.Default; // normal cursor
        }