private static Rectangle process(Gray<byte>[,] probabilityMap, Rectangle roi, TermCriteria termCriteria, out CentralMoments centralMoments)
{
Rectangle imageArea = new Rectangle(0, 0, probabilityMap.Width(), probabilityMap.Height());
Rectangle searchWindow = roi;
RawMoments moments = new RawMoments(order: 1);
// Mean shift with fixed number of iterations
int i = 0;
double shift = Byte.MaxValue;
while (termCriteria.ShouldTerminate(i, shift) == false && !searchWindow.IsEmptyArea())
{
// Locate first order moments
moments.Compute(probabilityMap, searchWindow);
int shiftX = (int)(moments.CenterX - searchWindow.Width / 2f);
int shiftY = (int)(moments.CenterY - searchWindow.Height / 2f);
// Shift the mean (centroid)
searchWindow.X += shiftX;
searchWindow.Y += shiftY;
// Keep the search window inside the image
searchWindow.Intersect(imageArea);
shift = System.Math.Abs((double)shiftX) + System.Math.Abs((double)shiftY); //for term criteria only
i++;
}
if (searchWindow.IsEmptyArea() == false)
{
// Locate second order moments and perform final shift
moments.Order = 2;
moments.Compute(probabilityMap, searchWindow);
searchWindow.X += (int)(moments.CenterX - searchWindow.Width / 2f);
searchWindow.Y += (int)(moments.CenterY - searchWindow.Height / 2f);
// Keep the search window inside the image
searchWindow.Intersect(imageArea);
}
centralMoments = new CentralMoments(moments); // moments to be used by camshift
return searchWindow;
}
/// <summary>
/// Computes the Hu moments from the specified central moments.
/// </summary>
///
/// <param name="moments">The central moments to use as base of calculations.</param>
///
public void Compute(CentralMoments moments)
{
double inv = 1.0 / moments.Mu00;
double inv2 = 1.0 / (moments.Mu00 * moments.Mu00);
double inv5d2 = System.Math.Sqrt(inv2 * inv2 * inv);
float n20 = (float)(moments.Mu20 * inv2);
float n02 = (float)(moments.Mu02 * inv2);
float n11 = (float)(moments.Mu11 * inv2);
float n21 = (float)(moments.Mu21 * inv5d2);
float n12 = (float)(moments.Mu12 * inv5d2);
float n30 = (float)(moments.Mu30 * inv5d2);
float n03 = (float)(moments.Mu03 * inv5d2);
// (η20 + η02)
I1 = (n20 + n02);
// (η20 − η02)² + 4 η11²
I2 = (n20 - n02) * (n20 - n02) + 4 * (n11 * n11);
// (η30 − 3 η12)²
I3 = (n30 - 3 * n12) * (n30 - 3 * n12)
// + (3 η21 − η03)²
+ (3 * n21 - n03) * (3 * n21 - n03);
// (η30 + η12)² + (η21 + η03)²
I4 = (n30 + n12) * (n30 + n12) + (n21 + n03) * (n21 + n03);
// (η30 − 3 η12) (η30 + η12) [(η30 + η12)² −3 (η21 + η03)² ]
I5 = (n30 - 3 * n12) * (n30 + n12) * ((n30 + n12) * (n30 + n12) - 3 * (n21 + n03) * (n21 + n03))
// (3 η21 − η03) (η21 + η03) [3 (η30 + η12)² − (η21 + η03)² ]
+ (3 * n21 - n03) * (n21 + n03) * (3 * (n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03));
// (η20 − η02) [(η30 + η12)² − (η21 + η03)² ]
I6 = (n20 - n02) * ((n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03))
// + 4 η11 (η30 + η12) (η21 + η03)
+ 4 * n11 * (n30 + n12) * (n21 + n03);
// (3 η21 − η03) (η30 + η12) [(η30 + η12)² − 3 (η21 + η03)² ]
I7 = (3 * n21 - n03) * (n30 + n12) * (n30 + n12) * ((n30 + n12) * (n30 + n12) - 3 * (n21 + n03) * (n21 + n03))
// - (η30 − 3 η12) (η21 + η03) [3 (η30 + η12)² − (η21 + η03)² ]
- (n30 - 3 * n12) * (n21 + n03) * (3 * (n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03));
}
/// <summary>
/// Computes moments for the provided image.
/// </summary>
/// <param name="image">Image.</param>
/// <param name="area">Area</param>
public void Compute(Gray <float>[,] image, Rectangle area)
{
RawMoments raw = new RawMoments(Order);
raw.Compute(image, area);
CentralMoments center = new CentralMoments(raw);
this.Compute(center);
}
/// <summary>
/// Camshift algorithm
/// </summary>
/// <param name="probabilityMap">Probability map [0-255].</param>
/// <param name="roi">Initial Search area</param>
/// <param name="termCriteria">Mean shift termination criteria (PLEASE DO NOT REMOVE (but you can move it) THIS CLASS; PLEASE!!!)</param>
/// <param name="centralMoments">Calculated central moments (up to order 2).</param>
/// <returns>Object position, size and angle packed into a structure.</returns>
public static Box2D Process(Gray<byte>[,] probabilityMap, Rectangle roi, TermCriteria termCriteria, out CentralMoments centralMoments)
{
// Compute mean shift
Rectangle objArea = Meanshift.Process(probabilityMap, roi, termCriteria, out centralMoments);
//fit ellipse
Ellipse ellipse = centralMoments.GetEllipse();
ellipse.Center = objArea.Center();
//return empty structure is the object is lost
var sz = ellipse.Size;
if (Single.IsNaN(sz.Width) || Single.IsNaN(sz.Height) ||
sz.Width < 1 || sz.Height < 1)
{
return Box2D.Empty;
}
return (Box2D)ellipse;
}
/// <summary>
/// Meanshift algorithm
/// </summary>
/// <param name="probabilityMap">Probability map [0-255].</param>
/// <param name="roi">Initial search area</param>
/// <param name="termCriteria">Mean shift termination criteria</param>
/// <param name="centralMoments">Calculated central moments (up to order 2).</param>
/// <returns>Object area.</returns>
public static Rectangle Process(Gray<byte>[,] probabilityMap, Rectangle roi, TermCriteria termCriteria, out CentralMoments centralMoments)
{
return process(probabilityMap, roi, termCriteria, out centralMoments);
}
/// <summary>
/// Computes moments for the provided image.
/// </summary>
/// <param name="image">Image.</param>
/// <param name="area">Area</param>
public void Compute(Gray<float>[,] image, Rectangle area)
{
RawMoments raw = new RawMoments(Order);
raw.Compute(image, area);
CentralMoments center = new CentralMoments(raw);
this.Compute(center);
}
/// <summary>
/// Computes the Hu moments from the specified central moments.
/// </summary>
///
/// <param name="moments">The central moments to use as base of calculations.</param>
///
public void Compute(CentralMoments moments)
{
double inv = 1.0 / moments.Mu00;
double inv2 = 1.0 / (moments.Mu00 * moments.Mu00);
double inv5d2 = System.Math.Sqrt(inv2 * inv2 * inv);
float n20 = (float)(moments.Mu20 * inv2);
float n02 = (float)(moments.Mu02 * inv2);
float n11 = (float)(moments.Mu11 * inv2);
float n21 = (float)(moments.Mu21 * inv5d2);
float n12 = (float)(moments.Mu12 * inv5d2);
float n30 = (float)(moments.Mu30 * inv5d2);
float n03 = (float)(moments.Mu03 * inv5d2);
// (η20 + η02)
I1 = (n20 + n02);
// (η20 − η02)² + 4 η11²
I2 = (n20 - n02) * (n20 - n02) + 4 * (n11 * n11);
// (η30 − 3 η12)²
I3 = (n30 - 3 * n12) * (n30 - 3 * n12)
// + (3 η21 − η03)²
+ (3 * n21 - n03) * (3 * n21 - n03);
// (η30 + η12)² + (η21 + η03)²
I4 = (n30 + n12) * (n30 + n12) + (n21 + n03) * (n21 + n03);
// (η30 − 3 η12) (η30 + η12) [(η30 + η12)² −3 (η21 + η03)² ]
I5 = (n30 - 3 * n12) * (n30 + n12) * ((n30 + n12) * (n30 + n12) - 3 * (n21 + n03) * (n21 + n03))
// (3 η21 − η03) (η21 + η03) [3 (η30 + η12)² − (η21 + η03)² ]
+ (3 * n21 - n03) * (n21 + n03) * (3 * (n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03));
// (η20 − η02) [(η30 + η12)² − (η21 + η03)² ]
I6 = (n20 - n02) * ((n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03))
// + 4 η11 (η30 + η12) (η21 + η03)
+ 4 * n11 * (n30 + n12) * (n21 + n03);
// (3 η21 − η03) (η30 + η12) [(η30 + η12)² − 3 (η21 + η03)² ]
I7 = (3 * n21 - n03) * (n30 + n12) * (n30 + n12) * ((n30 + n12) * (n30 + n12) - 3 * (n21 + n03) * (n21 + n03))
// - (η30 − 3 η12) (η21 + η03) [3 (η30 + η12)² − (η21 + η03)² ]
- (n30 - 3 * n12) * (n21 + n03) * (3 * (n30 + n12) * (n30 + n12) - (n21 + n03) * (n21 + n03));
}
