/// <summary>
/// 匹配較快速但精確度較低
/// </summary>
/// <param name="template">樣板的特徵點類別</param>
/// <param name="observedScene">被觀察的場景匹配的特徵點</param>
/// <returns>回傳匹配的資料類別</returns>
public static SURFMatchedData MatchSURFFeatureByFLANN(SURFFeatureData template, SURFFeatureData observedScene)
{
Matrix <byte> mask;
int k = 2;
double uniquenessThreshold = 0.3;
Matrix <int> indices;
HomographyMatrix homography = null;
Stopwatch watch;
Matrix <float> dists;
try
{
watch = Stopwatch.StartNew();
#region FLANN Match CPU
//match
Index flann = new Index(template.GetDescriptors(), 4);
indices = new Matrix <int>(observedScene.GetDescriptors().Rows, k);
using (dists = new Matrix <float>(observedScene.GetDescriptors().Rows, k))
{
flann.KnnSearch(observedScene.GetDescriptors(), indices, dists, k, 2);
mask = new Matrix <byte>(dists.Rows, 1);
mask.SetValue(255);
Features2DToolbox.VoteForUniqueness(dists, uniquenessThreshold, mask);
}
int nonZeroCount = CvInvoke.cvCountNonZero(mask);
Console.WriteLine("-----------------\nVoteForUniqueness pairCount => " + nonZeroCount.ToString() + "\n-----------------");
if (nonZeroCount >= 4) //原先是4
{
nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(template.GetKeyPoints(), observedScene.GetKeyPoints(), indices, mask, 1.2, 30);
Console.WriteLine("VoteForSizeAndOrientation pairCount => " + nonZeroCount.ToString() + "\n-----------------");
//filter out all unnecessary pairs based on distance between pairs
if (nonZeroCount >= 30) //原先是4
{
homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(template.GetKeyPoints(), observedScene.GetKeyPoints(), indices, mask, 5); //原先是5
}
}
#endregion
watch.Stop();
Console.WriteLine("Cal SURF Match time => " + watch.ElapsedMilliseconds.ToString() + "\n-----------------");
return(new SURFMatchedData(indices, homography, mask, nonZeroCount, template));
}
catch (CvException ex)
{
System.Windows.Forms.MessageBox.Show(ex.ErrorMessage);
return(null);
}
}
/// <summary>
/// 使用BruteForce匹配(較精確但較慢)
/// </summary>
/// <param name="template">樣板的特徵點類別</param>
/// <param name="observedScene">被觀察的場景匹配的特徵點</param>
/// <returns>回傳匹配的資料類別</returns>
public static SURFMatchedData MatchSURFFeatureByBruteForce(SURFFeatureData template, SURFFeatureData observedScene)
{
Matrix <byte> mask;
int k = 2;
double uniquenessThreshold = 0.5; //default:0.8
Matrix <int> indices;
HomographyMatrix homography = null;
Stopwatch watch;
try
{
watch = Stopwatch.StartNew();
#region bruteForce match for CPU
//match
BruteForceMatcher <float> matcher = new BruteForceMatcher <float>(DistanceType.L2Sqr); //default:L2
matcher.Add(template.GetDescriptors());
indices = new Matrix <int>(observedScene.GetDescriptors().Rows, k);
using (Matrix <float> dist = new Matrix <float>(observedScene.GetDescriptors().Rows, k))
{
matcher.KnnMatch(observedScene.GetDescriptors(), indices, dist, k, null);
mask = new Matrix <byte>(dist.Rows, 1);
mask.SetValue(255);
Features2DToolbox.VoteForUniqueness(dist, uniquenessThreshold, mask);
}
int nonZeroCount = CvInvoke.cvCountNonZero(mask);
Console.WriteLine("-----------------\nVoteForUniqueness pairCount => " + nonZeroCount.ToString() + "\n-----------------");
if (nonZeroCount >= 4)
{
nonZeroCount = Features2DToolbox.VoteForSizeAndOrientation(template.GetKeyPoints(), observedScene.GetKeyPoints(), indices, mask, 1.5, 30); //default:1.5 , 10, scale increment:1.5 rotatebin:50
Console.WriteLine("VoteForSizeAndOrientation pairCount => " + nonZeroCount.ToString() + "\n-----------------");
if (nonZeroCount >= 25) //defalut :4 , modify: 15
{
homography = Features2DToolbox.GetHomographyMatrixFromMatchedFeatures(template.GetKeyPoints(), observedScene.GetKeyPoints(), indices, mask, 5);
}
}
#endregion
watch.Stop();
Console.WriteLine("Cal SURF Match time => " + watch.ElapsedMilliseconds.ToString() + "\n-----------------");
return(new SURFMatchedData(indices, homography, mask, nonZeroCount, template));
}
catch (CvException ex)
{
System.Windows.Forms.MessageBox.Show(ex.ErrorMessage);
return(null);
}
}
