/// <summary>
/// computes the best-fit perspective transformation mapping srcPoints to dstPoints.
/// </summary>
/// <param name="srcPoints">Coordinates of the points in the original plane</param>
/// <param name="dstPoints">Coordinates of the points in the target plane</param>
/// <param name="method">Method used to computed a homography matrix.</param>
/// <param name="ransacReprojThreshold">Maximum allowed reprojection error to treat a point pair as an inlier (used in the RANSAC method only)</param>
/// <param name="mask"> Optional output mask set by a robust method ( CV_RANSAC or CV_LMEDS ). Note that the input mask values are ignored.</param>
/// <returns></returns>
public static Mat FindHomography(IEnumerable<Point2d> srcPoints, IEnumerable<Point2d> dstPoints,
HomographyMethods method = HomographyMethods.None, double ransacReprojThreshold = 3,
OutputArray mask = null)
{
if (srcPoints == null)
throw new ArgumentNullException("srcPoints");
if (dstPoints == null)
throw new ArgumentNullException("dstPoints");
Point2d[] srcPointsArray = EnumerableEx.ToArray(srcPoints);
Point2d[] dstPointsArray = EnumerableEx.ToArray(dstPoints);
IntPtr mat = NativeMethods.calib3d_findHomography_vector(srcPointsArray, srcPointsArray.Length,
dstPointsArray, dstPointsArray.Length, (int)method, ransacReprojThreshold, ToPtr(mask));
if (mask != null)
mask.Fix();
return new Mat(mat);
}
/// <summary>
/// Refines the matches with homography.
/// </summary>
/// <returns><c>true</c>, if matches with homography was refined, <c>false</c> otherwise.</returns>
/// <param name="queryKeypoints">Query keypoints.</param>
/// <param name="trainKeypoints">Train keypoints.</param>
/// <param name="reprojectionThreshold">Reprojection threshold.</param>
/// <param name="matches">Matches.</param>
/// <param name="homography">Homography.</param>
static bool refineMatchesWithHomography
(
KeyPoint[] queryKeypoints,
KeyPoint[] trainKeypoints,
float reprojectionThreshold,
ref DMatch[] matches,
ref Mat homography,
HomographyMethods methods
)
{
// Debug.Log ("matches " + matches.ToString ());
int minNumberMatchesAllowed = 8;
List <KeyPoint> queryKeypointsList = queryKeypoints.ToList();
List <KeyPoint> trainKeypointsList = trainKeypoints.ToList();
List <DMatch> matchesList = matches.ToList();
if (matchesList.Count < minNumberMatchesAllowed)
{
return(false);
}
// Prepare data for cv::findHomography
List <Point2f> srcPointsList = new List <Point2f> (matchesList.Count);
List <Point2f> dstPointsList = new List <Point2f> (matchesList.Count);
for (int i = 0; i < matchesList.Count; i++)
{
srcPointsList.Add(trainKeypointsList [matchesList [i].TrainIdx].Pt);
dstPointsList.Add(queryKeypointsList [matchesList [i].QueryIdx].Pt);
}
// Find homography matrix and get inliers mask
// Debug.Log ("srcPoints " + srcPoints.ToString ());
// Debug.Log ("dstPoints " + dstPoints.ToString ());
using (Mat srcPoints = new Mat(srcPointsList.Count, 2, MatType.CV_32F, srcPointsList.ToArray()))
using (Mat dstPoints = new Mat(dstPointsList.Count, 2, MatType.CV_32F, dstPointsList.ToArray()))
using (var inliersMask = new Mat(srcPointsList.Count, 1, MatType.CV_8U))
{
//homography=Cv2.FindHomography(InputArray.Create( srcPointsList), InputArray.Create(dstPointsList), HomographyMethods.Ransac, reprojectionThreshold, inliersMask);
homography = Cv2.FindHomography(srcPoints, dstPoints, methods, reprojectionThreshold, inliersMask);
if (homography.Rows != 3 || homography.Cols != 3)
{
return(false);
}
List <DMatch> inliers = new List <DMatch>();
for (int i = 0; i < inliersMask.Rows; i++)
{
if (inliersMask.Get <byte>(i, 0) == 1)
{
inliers.Add(matchesList[i]);
}
}
matches = inliers.ToArray();
}
return(matchesList.Count > minNumberMatchesAllowed);
}
/// <summary>
/// computes the best-fit perspective transformation mapping srcPoints to dstPoints.
/// </summary>
/// <param name="srcPoints">Coordinates of the points in the original plane, a matrix of the type CV_32FC2</param>
/// <param name="dstPoints">Coordinates of the points in the target plane, a matrix of the type CV_32FC2</param>
/// <param name="method">Method used to computed a homography matrix.</param>
/// <param name="ransacReprojThreshold">Maximum allowed reprojection error to treat a point pair as an inlier (used in the RANSAC method only)</param>
/// <param name="mask"> Optional output mask set by a robust method ( CV_RANSAC or CV_LMEDS ). Note that the input mask values are ignored.</param>
/// <returns></returns>
public static Mat FindHomography(InputArray srcPoints, InputArray dstPoints,
HomographyMethods method = HomographyMethods.None, double ransacReprojThreshold = 3,
OutputArray mask = null)
{
if (srcPoints == null)
throw new ArgumentNullException("srcPoints");
if (dstPoints == null)
throw new ArgumentNullException("dstPoints");
srcPoints.ThrowIfDisposed();
dstPoints.ThrowIfDisposed();
IntPtr mat = NativeMethods.calib3d_findHomography_InputArray(srcPoints.CvPtr, dstPoints.CvPtr, (int)method,
ransacReprojThreshold, ToPtr(mask));
if (mask != null)
mask.Fix();
return new Mat(mat);
}