private Bitmap HoughTransform(Bitmap originalImage)
{
var imgBitmap = new Bitmap(originalImage);
var lineTransform = new Accord.Imaging.HoughLineTransformation();
// Convert it to binary and mark the possible lines
// in white so it can be processed by the transform
var sequence = new FiltersSequence(
Grayscale.CommonAlgorithms.BT709,
new NiblackThreshold(),
new Invert()
);
var contoursBitmap = ImageFilter.PrewittFilter(imgBitmap, true);
// Apply the sequence of filters above:
Bitmap binaryImage = sequence.Apply(contoursBitmap);
lineTransform.ProcessImage(binaryImage);
// Now, let's say we would like to retrieve the lines and use them
// for further processing. First, the lines can be ordered by their
// relative intensity using
HoughLine[] lines = lineTransform.GetLinesByRelativeIntensity(1);
// Then, let's plot them on top of the input image. Since we will
// apply many operations to a single image, it is better to first
// convert it to an UnmanagedImage object to avoid having to lock
// the image into memory multiple times.
UnmanagedImage unmanagedImage = UnmanagedImage.FromManagedImage(binaryImage);
// Finally, plot them in order:
foreach (HoughLine line in lines)
{
line.Draw(unmanagedImage, color: Color.Red);
}
return(unmanagedImage.ToManagedImage());
}
