public void TestBruteForceHammingDistance()
{
if (CudaInvoke.HasCuda)
{
Image <Gray, byte> box = new Image <Gray, byte>("box.png");
FastDetector fast = new FastDetector(100, true);
BriefDescriptorExtractor brief = new BriefDescriptorExtractor(32);
#region extract features from the object image
Stopwatch stopwatch = Stopwatch.StartNew();
VectorOfKeyPoint modelKeypoints = new VectorOfKeyPoint();
fast.DetectRaw(box, modelKeypoints);
Mat modelDescriptors = new Mat();
brief.Compute(box, modelKeypoints, modelDescriptors);
stopwatch.Stop();
Trace.WriteLine(String.Format("Time to extract feature from model: {0} milli-sec", stopwatch.ElapsedMilliseconds));
#endregion
Image <Gray, Byte> observedImage = new Image <Gray, byte>("box_in_scene.png");
#region extract features from the observed image
stopwatch.Reset(); stopwatch.Start();
VectorOfKeyPoint observedKeypoints = new VectorOfKeyPoint();
fast.DetectRaw(observedImage, observedKeypoints);
Mat observedDescriptors = new Mat();
brief.Compute(observedImage, observedKeypoints, observedDescriptors);
stopwatch.Stop();
Trace.WriteLine(String.Format("Time to extract feature from image: {0} milli-sec", stopwatch.ElapsedMilliseconds));
#endregion
HomographyMatrix homography = null;
using (GpuMat <Byte> gpuModelDescriptors = new GpuMat <byte>(modelDescriptors)) //initialization of GPU code might took longer time.
{
stopwatch.Reset(); stopwatch.Start();
CudaBruteForceMatcher hammingMatcher = new CudaBruteForceMatcher(DistanceType.Hamming);
//BruteForceMatcher hammingMatcher = new BruteForceMatcher(BruteForceMatcher.DistanceType.Hamming, modelDescriptors);
int k = 2;
Matrix <int> trainIdx = new Matrix <int>(observedKeypoints.Size, k);
Matrix <float> distance = new Matrix <float>(trainIdx.Size);
using (GpuMat <Byte> gpuObservedDescriptors = new GpuMat <byte>(observedDescriptors))
//using (GpuMat<int> gpuTrainIdx = new GpuMat<int>(trainIdx.Rows, trainIdx.Cols, 1, true))
//using (GpuMat<float> gpuDistance = new GpuMat<float>(distance.Rows, distance.Cols, 1, true))
using (VectorOfVectorOfDMatch matches = new VectorOfVectorOfDMatch())
{
Stopwatch w2 = Stopwatch.StartNew();
hammingMatcher.KnnMatch(gpuObservedDescriptors, gpuModelDescriptors, matches, k);
w2.Stop();
Trace.WriteLine(String.Format("Time for feature matching (excluding data transfer): {0} milli-sec",
w2.ElapsedMilliseconds));
//gpuTrainIdx.Download(trainIdx);
//gpuDistance.Download(distance);
Matrix <Byte> mask = new Matrix <byte>(distance.Rows, 1);
mask.SetValue(255);
Features2DToolbox.VoteForUniqueness(matches, 0.8, mask);
int nonZeroCount = CvInvoke.CountNonZero(mask);
if (nonZeroCount >= 4)
{
nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeypoints, observedKeypoints,
matches, mask, 1.5, 20);
if (nonZeroCount >= 4)
{
homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(modelKeypoints,
observedKeypoints, matches, mask, 2);
}
nonZeroCount = CvInvoke.CountNonZero(mask);
}
stopwatch.Stop();
Trace.WriteLine(String.Format("Time for feature matching (including data transfer): {0} milli-sec",
stopwatch.ElapsedMilliseconds));
}
}
if (homography != null)
{
Rectangle rect = box.ROI;
PointF[] pts = new PointF[] {
new PointF(rect.Left, rect.Bottom),
new PointF(rect.Right, rect.Bottom),
new PointF(rect.Right, rect.Top),
new PointF(rect.Left, rect.Top)
};
PointF[] points = pts.Clone() as PointF[];
homography.ProjectPoints(points);
//Merge the object image and the observed image into one big image for display
Image <Gray, Byte> res = box.ConcateVertical(observedImage);
for (int i = 0; i < points.Length; i++)
{
points[i].Y += box.Height;
}
res.DrawPolyline(Array.ConvertAll <PointF, Point>(points, Point.Round), true, new Gray(255.0), 5);
//ImageViewer.Show(res);
}
}
}
public static void FindMatch(Image <Gray, Byte> modelImage, Image <Gray, byte> observedImage, out long matchTime, out VectorOfKeyPoint modelKeyPoints, out VectorOfKeyPoint observedKeyPoints, VectorOfVectorOfDMatch matches, out Matrix <byte> mask, out HomographyMatrix homography)
{
int k = 2;
double uniquenessThreshold = 0.8;
double hessianThresh = 300;
Stopwatch watch;
homography = null;
modelKeyPoints = new VectorOfKeyPoint();
observedKeyPoints = new VectorOfKeyPoint();
#if !IOS
if (CudaInvoke.HasCuda)
{
CudaSURFDetector surfCuda = new CudaSURFDetector((float)hessianThresh);
using (GpuMat gpuModelImage = new GpuMat(modelImage))
//extract features from the object image
using (GpuMat gpuModelKeyPoints = surfCuda.DetectKeyPointsRaw(gpuModelImage, null))
using (GpuMat gpuModelDescriptors = surfCuda.ComputeDescriptorsRaw(gpuModelImage, null, gpuModelKeyPoints))
using (CudaBruteForceMatcher matcher = new CudaBruteForceMatcher(DistanceType.L2))
{
surfCuda.DownloadKeypoints(gpuModelKeyPoints, modelKeyPoints);
watch = Stopwatch.StartNew();
// extract features from the observed image
using (GpuMat gpuObservedImage = new GpuMat(observedImage))
using (GpuMat gpuObservedKeyPoints = surfCuda.DetectKeyPointsRaw(gpuObservedImage, null))
using (GpuMat gpuObservedDescriptors = surfCuda.ComputeDescriptorsRaw(gpuObservedImage, null, gpuObservedKeyPoints))
//using (GpuMat tmp = new GpuMat())
//using (Stream stream = new Stream())
{
matcher.KnnMatch(gpuObservedDescriptors, gpuModelDescriptors, matches, k);
surfCuda.DownloadKeypoints(gpuObservedKeyPoints, observedKeyPoints);
mask = new Matrix <byte>(matches.Size, 1);
mask.SetValue(255);
Features2DToolbox.VoteForUniqueness(matches, uniquenessThreshold, mask);
int nonZeroCount = CvInvoke.CountNonZero(mask);
if (nonZeroCount >= 4)
{
nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeyPoints, observedKeyPoints,
matches, mask, 1.5, 20);
if (nonZeroCount >= 4)
{
homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(modelKeyPoints,
observedKeyPoints, matches, mask, 2);
}
}
}
watch.Stop();
}
}
else
#endif
{
using (UMat uModelImage = modelImage.Mat.ToUMat(AccessType.Read))
using (UMat uObservedImage = observedImage.Mat.ToUMat(AccessType.Read))
{
SURFDetector surfCPU = new SURFDetector(hessianThresh);
//extract features from the object image
UMat modelDescriptors = new UMat();
surfCPU.DetectAndCompute(uModelImage, null, modelKeyPoints, modelDescriptors, false);
watch = Stopwatch.StartNew();
// extract features from the observed image
UMat observedDescriptors = new UMat();
surfCPU.DetectAndCompute(uObservedImage, null, observedKeyPoints, observedDescriptors, false);
BruteForceMatcher matcher = new BruteForceMatcher(DistanceType.L2);
matcher.Add(modelDescriptors);
matcher.KnnMatch(observedDescriptors, matches, k, null);
mask = new Matrix <byte>(matches.Size, 1);
mask.SetValue(255);
Features2DToolbox.VoteForUniqueness(matches, uniquenessThreshold, mask);
int nonZeroCount = CvInvoke.CountNonZero(mask);
if (nonZeroCount >= 4)
{
nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(modelKeyPoints, observedKeyPoints,
matches, mask, 1.5, 20);
if (nonZeroCount >= 4)
{
homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(modelKeyPoints,
observedKeyPoints, matches, mask, 2);
}
}
watch.Stop();
}
}
matchTime = watch.ElapsedMilliseconds;
}
