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CvInvokeCalcMotionGradient Method
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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.World (in Emgu.CV.World.dll) Version: 3.1.0.2282 (3.1.0.2282)
Syntax
public static void CalcMotionGradient(
	IInputArray mhi,
	IOutputArray mask,
	IOutputArray orientation,
	double delta1,
	double delta2,
	int apertureSize = 3
)

Parameters

mhi
Type: Emgu.CVIInputArray
Motion history image
mask
Type: Emgu.CVIOutputArray
Mask image; marks pixels where motion gradient data is correct. Output parameter.
orientation
Type: Emgu.CVIOutputArray
Motion gradient orientation image; contains angles from 0 to ~360.
delta1
Type: SystemDouble
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: SystemDouble
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 (Optional)
Type: SystemInt32
Aperture size of derivative operators used by the function: CV_SCHARR, 1, 3, 5 or 7 (see cvSobel).
See Also