How to get Foot pressure impression by a camera integrated device

private void cmb_cameras_SelectedIndexChanged(object sender, EventArgs e)
{
    //selected video source
    FinalVideoSource = new VideoCaptureDevice(VideoCaptureDevices[cmb_cameras.SelectedIndex].MonikerString);
    FinalVideoSource.NewFrame += new NewFrameEventHandler(FinalVideoSource_NewFrame);
    FinalVideoSource.Start();
}
void FinalVideoSource_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
    try
    {
        //System.Console.WriteLine("1: Flag status: " + flag.ToString());
        if (flag!=true)
        {
            flag = true;
            //System.Console.WriteLine("2: Flag status: "+ flag.ToString());
            lock (NewBitmap)
            {
                using (ImageAttributes attributes = new ImageAttributes())
                {                            
                    LiveImage = (Bitmap)eventArgs.Frame.Clone();
                    Graphics g = Graphics.FromImage(NewBitmap);
                    //create the grayscale ColorMatrix
                    ColorMatrix colorMatrix = new ColorMatrix(
                     new float[][]
                    {
                         new float[] {.3f, .3f, .3f, 0, 0},
                         new float[] {.59f, .59f, .59f, 0, 0},
                         new float[] {.11f, .11f, .11f, 0, 0},
                         new float[] {0, 0, 0, 1, 0},
                         new float[] {0, 0, 0, 0, 1}
                    });
                    attributes.SetColorMatrix(colorMatrix);
                    //draw the original image on the new image
                    //using the grayscale color matrix
                    g.DrawImage(LiveImage, new Rectangle(0, 0, 640, 480),
                      0, 0, 640, 480, GraphicsUnit.Pixel, attributes);

     //--------------------------- Method 2ND ----------------------------------
                   // System.Diagnostics.Stopwatch sWatch = new System.Diagnostics.Stopwatch();
                   // sWatch.Start();
                   // PB_LiveImage.Image = LiveImage;
                    PB_LiveImage.Image = ChangeColor();
                    //sWatch.Stop();
                    //MessageBox.Show(sWatch.ElapsedMilliseconds.ToString());

                    
                }
            }
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show("Message:\n\nKindly closed the application.\nOne unhandled exception has been occurred!!");
    }  
}

public unsafe Bitmap ChangeColor()
{            
    Bitmap bmp = new Bitmap(NewBitmap);
    LockBitClass lockBitmap = new LockBitClass(bmp);
    lockBitmap.LockBits();
    Color compareClr = Color.FromArgb(75, 75, 75);
    Color compareClr2 = Color.FromArgb(90, 90, 90);
    Color compareClr3 = Color.FromArgb(105, 105, 105);
    Color compareClr4 = Color.FromArgb(150, 150, 150);
    for (int y = 0; y < lockBitmap.Height; y++)
    {
        for (int x = 0; x < lockBitmap.Width; x++)
        {

            //Console.WriteLine((System.Drawing.Color.LightGray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb()) + " LightGray");
            //Console.WriteLine((System.Drawing.Color.Gray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb()) + " Gray");
            //Console.WriteLine((System.Drawing.Color.DarkGray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb()) + " DarkGray");
            if (System.Drawing.Color.LightGray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb())                        
                lockBitmap.SetPixel(x, y, Color.Cyan);
            else if (System.Drawing.Color.Gray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb())
                lockBitmap.SetPixel(x, y, Color.Yellow);
            else if (System.Drawing.Color.DarkGray.ToArgb() == lockBitmap.GetPixel(x, y).ToArgb())
                lockBitmap.SetPixel(x, y, Color.Red);
            else
                lockBitmap.SetPixel(x, y, Color.Blue);
        }
    }
    lockBitmap.UnlockBits();
    
    return bmp;
}