/// <summary>
/// Compute the descriptor given the image and the point location
/// </summary>
/// <param name="image">The image where the descriptor will be computed from</param>
/// <param name="mask">The optional mask, can be null if not needed</param>
/// <param name="keyPoints">The keypoint where the descriptor will be computed from</param>
/// <returns>The image features founded on the keypoint location</returns>
public ImageFeature[] ComputeDescriptors(Image <Gray, Byte> image, Image <Gray, byte> mask, MKeyPoint[] keyPoints)
{
using (VectorOfFloat descs = new VectorOfFloat())
{
GCHandle handle = GCHandle.Alloc(keyPoints, GCHandleType.Pinned);
CvSURFDetectorComputeDescriptors(ref this, image, mask, handle.AddrOfPinnedObject(), keyPoints.Length, descs);
handle.Free();
int n = keyPoints.Length;
long address = descs.StartAddress.ToInt64();
ImageFeature[] features = new ImageFeature[n];
int sizeOfdescriptor = extended == 0 ? 64 : 128;
for (int i = 0; i < n; i++, address += sizeOfdescriptor * sizeof(float))
{
features[i].KeyPoint = keyPoints[i];
float[] desc = new float[sizeOfdescriptor];
Marshal.Copy(new IntPtr(address), desc, 0, sizeOfdescriptor);
features[i].Descriptor = desc;
}
return(features);
}
}
/// <summary>
/// Detect image features from the given image
/// </summary>
/// <param name="image">The image to detect features from</param>
/// <param name="mask">The optional mask, can be null if not needed</param>
/// <returns>The Image features detected from the given image</returns>
public ImageFeature[] DetectFeatures(Image <Gray, Byte> image, Image <Gray, byte> mask)
{
using (MemStorage stor = new MemStorage())
using (VectorOfFloat descs = new VectorOfFloat())
{
Seq <MKeyPoint> pts = new Seq <MKeyPoint>(stor);
CvSURFDetectorDetectFeature(ref this, image, mask, pts, descs);
MKeyPoint[] kpts = pts.ToArray();
int n = kpts.Length;
long add = descs.StartAddress.ToInt64();
ImageFeature[] features = new ImageFeature[n];
int sizeOfdescriptor = extended == 0 ? 64 : 128;
for (int i = 0; i < n; i++, add += sizeOfdescriptor * sizeof(float))
{
features[i].KeyPoint = kpts[i];
float[] desc = new float[sizeOfdescriptor];
Marshal.Copy(new IntPtr(add), desc, 0, sizeOfdescriptor);
features[i].Descriptor = desc;
}
return(features);
}
}
