Threshold binarization.
The filter does image binarization using specified threshold value. All pixels with intensities equal or higher than threshold value are converted to white pixels. All other pixels with intensities below threshold value are converted to black pixels.
The filter accepts 8 and 16 bpp grayscale images for processing.
Sample usage:
// create filter Threshold filter = new Threshold( 100 ); // apply the filter filter.ApplyInPlace( image ); Initial image:
Result image:
private void SetFilter()
{
ImageType = ImageTypes.Rgb24bpp;
Af.Threshold newFilter = new Af.Threshold();
newFilter.ThresholdValue = threshold;
imageFilter = newFilter;
}
private void captureHand(UnmanagedImage mask, Rectangle rect, PictureBox pbArm, PictureBox pbHand)
{
Crop c = new Crop(rect);
var handImage = c.Apply(mask);
var ps = handImage.Collect16bppPixelValues(handImage.CollectActivePixels());
if (ps.Length > 0)
{
ushort max = Matrix.Max(ps);
LevelsLinear16bpp levels = new LevelsLinear16bpp();
levels.InGray = new IntRange(0, max);
levels.OutGray = new IntRange(0, 65535);
levels.ApplyInPlace(handImage);
// pbArm.Image = handImage.ToManagedImage();
double cutoff = 30000;
Threshold th = new Threshold((int)cutoff);
var handMask = th.Apply(handImage);
var handMask8bit = Accord.Imaging.Image.Convert16bppTo8bpp(handMask.ToManagedImage());
BlobCounter bch = new BlobCounter();
bch.ObjectsOrder = ObjectsOrder.Area;
bch.ProcessImage(handMask8bit);
var blob = bch.GetObjectsInformation();
if (blob.Length > 0)
{
Intersect inters = new Intersect();
inters.UnmanagedOverlayImage = handMask;
inters.ApplyInPlace(handImage);
Crop ch = new Crop(blob[0].Rectangle);
handImage = ch.Apply(handImage);
ResizeNearestNeighbor res = new ResizeNearestNeighbor(25, 25);
handImage = res.Apply(handImage);
var leftHand = Accord.Imaging.Image.Convert16bppTo8bpp(handImage.ToManagedImage());
pbHand.Image = leftHand;
}
}
}
private void videoSourcePlayer1_NewFrame(object sender, ref Bitmap image)
{
Invert inv = new Invert();
inv.ApplyInPlace(image);
UnmanagedImage ui = UnmanagedImage.FromManagedImage(image);
pictureBox1.Image = image;
if (controller.Tracker.TrackingObject == null)
return;
if (controller.Tracker.TrackingObject.IsEmpty)
return;
var rect = controller.Tracker.TrackingObject.Rectangle;
Crop crop = new Crop(rect);
UnmanagedImage head = crop.Apply(ui);
var points = new List<IntPoint>() { new IntPoint(head.Width / 2, head.Height / 2) };
var pps = head.Collect16bppPixelValues(points);
double mean = pps.Mean();
double cutoff = mean + 15;
Threshold t = new Threshold((int)cutoff);
var mask = t.Apply(ui);
LevelsLinear16bpp levels = new LevelsLinear16bpp();
levels.InGray = new IntRange((int)cutoff, 65535);
levels.OutGray = new IntRange(0, 65535);
levels.ApplyInPlace(ui);
var mask8bit = Accord.Imaging.Image.Convert16bppTo8bpp(mask.ToManagedImage());
BlobCounter bc = new BlobCounter();
bc.ObjectsOrder = ObjectsOrder.Area;
bc.ProcessImage(mask8bit);
var blobs = bc.GetObjectsInformation();
inv.ApplyInPlace(image);
Intersect intersect = new Intersect();
intersect.UnmanagedOverlayImage = mask;
mask = intersect.Apply(ui);
List<Rectangle> rects = new List<Rectangle>();
// Extract the uppermost largest blobs.
for (int i = 0; i < blobs.Length; i++)
{
double dx = (blobs[i].Rectangle.Top - controller.Tracker.TrackingObject.Center.Y);
double d = (dx * dx) / controller.Tracker.TrackingObject.Area;
if (d < 2 && blobs[i].Area > 1000)
rects.Add(blobs[i].Rectangle);
}
rects.Sort(compare);
if (rects.Count > 0)
{
captureHand(mask, rects[0], pbLeftArm, pbLeftHand);
}
if (rects.Count > 1)
{
captureHand(mask, rects[1], pbRightArm, pbRightHand);
}
RectanglesMarker marker = new RectanglesMarker(rects);
marker.MarkerColor = Color.White;
marker.ApplyInPlace(mask8bit);
image = mask.ToManagedImage();
}
