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Calculates the derivatives Dx and Dy of mhi and then calculates gradient orientation as: orientation(x,y)=arctan(Dy(x,y)/Dx(x,y)) where both Dx(x,y)' and Dy(x,y)' signs are taken into account (as in cvCartToPolar function). After that mask is filled to indicate where the orientation is valid (see delta1 and delta2 description).

Namespace: Emgu.CV
Assembly: Emgu.CV (in Emgu.CV.dll) Version: 2.4.0.1717 (2.4.0.1717)

Syntax

C#
public static void cvCalcMotionGradient(
	IntPtr mhi,
	IntPtr mask,
	IntPtr orientation,
	double delta1,
	double delta2,
	int apertureSize
)
Visual Basic
Public Shared Sub cvCalcMotionGradient ( _
	mhi As IntPtr, _
	mask As IntPtr, _
	orientation As IntPtr, _
	delta1 As Double, _
	delta2 As Double, _
	apertureSize As Integer _
)
Visual C++
public:
static void cvCalcMotionGradient(
	IntPtr mhi, 
	IntPtr mask, 
	IntPtr orientation, 
	double delta1, 
	double delta2, 
	int apertureSize
)

Parameters

mhi
Type: System..::..IntPtr
Motion history image
mask
Type: System..::..IntPtr
Mask image; marks pixels where motion gradient data is correct. Output parameter.
orientation
Type: System..::..IntPtr
Motion gradient orientation image; contains angles from 0 to ~360.
delta1
Type: System..::..Double
The function finds minimum (m(x,y)) and maximum (M(x,y)) mhi values over each pixel (x,y) neihborhood and assumes the gradient is valid only if min(delta1,delta2) <= M(x,y)-m(x,y) <= max(delta1,delta2).
delta2
Type: System..::..Double
The function finds minimum (m(x,y)) and maximum (M(x,y)) mhi values over each pixel (x,y) neihborhood and assumes the gradient is valid only if min(delta1,delta2) <= M(x,y)-m(x,y) <= max(delta1,delta2).
apertureSize
Type: System..::..Int32
Aperture size of derivative operators used by the function: CV_SCHARR, 1, 3, 5 or 7 (see cvSobel).

See Also