public static Rectangle GetRect(HoughTransform houghTransform)
{
if (houghTransform == null)
{
throw new ArgumentNullException(nameof(houghTransform));
}
houghTransform.ThrowIfDisposed();
HoughTransform.Native.hough_transform_get_rect(houghTransform.NativePtr, out var rect);
return(new Rectangle(rect));
}
private static void Main()
{
using (var img = new Array2D <byte>(400, 400))
using (var ht = new DlibDotNet.HoughTransform(300))
using (var win = new ImageWindow())
using (var win2 = new ImageWindow())
{
var angle1 = 0d;
var angle2 = 0d;
while (true)
{
angle1 += Math.PI / 130;
angle2 += Math.PI / 400;
var rect = img.Rect;
var cent = rect.Center;
var arc = Point.Rotate(cent, cent + new Point(90, 0), angle1 * 180 / Math.PI);
var tmp2 = arc + new Point(500, 0);
var tmp3 = arc - new Point(500, 0);
var l = Point.Rotate(arc, tmp2, angle2 * 180 / Math.PI);
var r = Point.Rotate(arc, tmp3, angle2 * 180 / Math.PI);
Dlib.AssignAllPixels(img, 0);
Dlib.DrawLine(img, l, r, 255);
using (var himg = new Array2D <int>())
{
var offset = new Point(50, 50);
var hrect = Dlib.GetRect(ht);
var box = Rectangle.Translate(hrect, offset);
// Now let's compute the hough transform for a subwindow in the image. In
// particular, we run it on the 300x300 subwindow with an upper left corner at the
// pixel point(50,50). The output is stored in himg.
ht.Operator(img, box, himg);
// Now that we have the transformed image, the Hough image pixel with the largest
// value should indicate where the line is. So we find the coordinates of the
// largest pixel:
using (var mat = Dlib.Mat(himg))
{
var p = Dlib.MaxPoint(mat);
// And then ask the ht object for the line segment in the original image that
// corresponds to this point in Hough transform space.
var line = ht.GetLine(p);
// Finally, let's display all these things on the screen. We copy the original
// input image into a color image and then draw the detected line on top in red.
using (var temp = new Array2D <RgbPixel>())
{
Dlib.AssignImage(img, temp);
var p1 = line.Item1 + offset;
var p2 = line.Item2 + offset;
Dlib.DrawLine(temp, p1, p2, new RgbPixel
{
Red = 255
});
win.ClearOverlay();
win.SetImage(temp);
// Also show the subwindow we ran the Hough transform on as a green box. You will
// see that the detected line is exactly contained within this box and also
// overlaps the original line.
win.AddOverlay(box, new RgbPixel
{
Green = 255
});
using (var jet = Dlib.Jet(himg))
win2.SetImage(jet);
}
}
}
}
}
}