private static float CalculateSecondError(KeyPairsTriangle triangle)
{
var dist1 = triangle.FirstPair.Key.GetDistance(triangle.SecondPair.Key);
var dist2 = triangle.SecondPair.Key.GetDistance(triangle.ThirdPair.Key);
var dist3 = triangle.ThirdPair.Key.GetDistance(triangle.FirstPair.Key);
return(Math.Abs(dist1 - dist2) + Math.Abs(dist1 - dist3));
}
public static KeyPairsTriangle RansacAlgorithm(
Dictionary <KeyPoint, KeyPoint> pointPairs,
int iterationsCount = 100,
float r = 10,
float R = 180,
bool countSecondError = false)
{
KeyPairsTriangle bestTriangle = null;
Mat bestCurrentTransform = null;
var minError = float.MaxValue;
var minSecondError = float.MaxValue;
for (int i = 0; i < iterationsCount; i++)
{
var triangle = ChooseTriangle(pointPairs, r, R);
if (triangle == null)
{
continue;
}
// For print image
var _currentTransform = CvInvoke.GetAffineTransform(triangle.GetFirstImageTriangle(), triangle.GetSecondImageTriangle());
if (_currentTransform.IsEmpty)
{
continue;
}
var error = CalculateError(_currentTransform, pointPairs);
if (error <= minError)
{
if (countSecondError)
{
var secondError = CalculateSecondError(triangle);
if (secondError <= minSecondError)
{
bestCurrentTransform = _currentTransform;
minError = error;
bestTriangle = triangle;
}
}
else
{
bestCurrentTransform = _currentTransform;
minError = error;
bestTriangle = triangle;
}
}
}
return(bestTriangle);
}
public static Dictionary <KeyPoint, KeyPoint> RansacFilterKeyPoint(Dictionary <KeyPoint, KeyPoint> pointPairs, KeyPairsTriangle traingle, float R)
{
var ransacKeyPoints = new Dictionary <KeyPoint, KeyPoint>();
foreach (var _keyPoint in pointPairs)
{
int i = 0;
foreach (var _pairs in traingle.GetTrianglePairs())
{
var _dist1 = _keyPoint.Key.GetDistance(_pairs.Key);
var _dist2 = _keyPoint.Value.GetDistance(_pairs.Value);
if (_dist1 < R && _dist2 < R)
{
i++;
}
}
if (i == 3)
{
ransacKeyPoints.Add(_keyPoint.Key, _keyPoint.Value);
}
}
return(ransacKeyPoints);
}
