Emgu CV Library Documentation
cvCalcOpticalFlowBM Method (prev, curr, block_size, shift_size, max_range, use_previous, velx, vely)
NamespacesEmgu.CVCvInvokecvCalcOpticalFlowBM(IntPtr, IntPtr, MCvSize, MCvSize, MCvSize, Int32, IntPtr, IntPtr)

www.emgu.com/wiki
Calculates optical flow for overlapped blocks block_size.width * block_size.height pixels each, thus the velocity fields are smaller than the original images. For every block in prev the functions tries to find a similar block in curr in some neighborhood of the original block or shifted by (velx(x0,y0),vely(x0,y0)) block as has been calculated by previous function call (if use_previous=1)
Declaration Syntax
C#Visual BasicVisual C++
public static void cvCalcOpticalFlowBM(
	IntPtr prev,
	IntPtr curr,
	MCvSize block_size,
	MCvSize shift_size,
	MCvSize max_range,
	int use_previous,
	IntPtr velx,
	IntPtr vely
)
Public Shared Sub cvCalcOpticalFlowBM ( _
	prev As IntPtr, _
	curr As IntPtr, _
	block_size As MCvSize, _
	shift_size As MCvSize, _
	max_range As MCvSize, _
	use_previous As Integer, _
	velx As IntPtr, _
	vely As IntPtr _
)
public:
static void cvCalcOpticalFlowBM(
	IntPtr prev, 
	IntPtr curr, 
	MCvSize block_size, 
	MCvSize shift_size, 
	MCvSize max_range, 
	int use_previous, 
	IntPtr velx, 
	IntPtr vely
)
Parameters
prev (IntPtr)
First image, 8-bit, single-channel.
curr (IntPtr)
Second image, 8-bit, single-channel.
block_size (MCvSize)
Size of basic blocks that are compared.
shift_size (MCvSize)
Block coordinate increments.
max_range (MCvSize)
Size of the scanned neighborhood in pixels around block.
use_previous (Int32)
Uses previous (input) velocity field.
velx (IntPtr)
Horizontal component of the optical flow of floor((prev->width - block_size.width)/shiftSize.width) x floor((prev->height - block_size.height)/shiftSize.height) size, 32-bit floating-point, single-channel.
vely (IntPtr)
Vertical component of the optical flow of the same size velx, 32-bit floating-point, single-channel.

Assembly: Emgu.CV (Module: Emgu.CV) Version: 1.3.0.0 (1.3.0.0)