MontiVision DirectShow SDK Documentation

The IMVConvolution interface is used to control the filter's image processing algorithm. Read the filter description to see how the filter is used. Read the remarks for implementation details.

get_NumOfKernels	Returns the number of kernels used for convolution.
put_NumOfKernels	Sets the number of kernels used for convolution.
get_SelectedKernel	Returns the index of the kernel that is currently being modified.
put_SelectedKernel	Sets the curent kernel index to be modified.
get_KernelCombination	Returns the current kernel combination method.
put_KernelCombination	Sets the current kernel combination method.
get_NumOfKernelColumns	Returns the number of columns in the currently selected kernel.
put_NumOfKernelColumns	Sets the number of columns in the currently selected kernel.
get_NumOfKernelRows	Returns the number of rows in the currently selected kernel.
put_NumOfKernelRows	Sets the number of rows in the currently selected kernel.
GetKernelValue	Returns the kernel value at the specified position [X,Y].
SetKernelValue	Sets the kernel value at the specified position [X,Y].
get_XAnchor	Returns the horizontal anchor of the currently selected kernel.
put_XAnchor	Sets the horizontal anchor of the currently selected kernel.
get_YAnchor	Returns the vetical anchor of the currently selected kernel.
put_YAnchor	Sets the vertical anchor of the currently selected kernel.
get_RightShift	Returns the pixel right shift of the currently selected kernel.
put_RightShift	Sets the pixel right shift of the currently selected kernel.

Header file: iMVConvolution.h
Interface definition language file: iMVConvolution.idl
Typelib: MVConvolution
Interface ID: IID_IMVConvolution

HRESULT get_NumOfKernels( [out, retval] int *piNumOfKernels );

Returns the number of kernels used to convolve with the video frames.

Parameter:

piNumOfKernels

A pointer to an integer value that receives the number of kernels.

HRESULT put_NumOfKernels( [in ] int iNumOfKernels );

Sets the number of kernels used to convolve with the video frames.

Parameter:

iNumOfKernels

The number of kernels.

HRESULT get_SelectedKernel( [out, retval] int *piSelectedKernel );

Returns the currently selected kernel.

Parameter:

piSelectedChannel

A pointer to an integer value that receives the number of thel kernel that is currently selected.

HRESULT put_SelectedKernel( [in ] int iSelectedKernel );

Sets the currently selected kernel.

Parameter:

iSelectedChannel

The number of the kernel to be modified.

HRESULT get_KernelCombination( [out, retval] int *piCombination );

Returns the method for kernel combination as MV_KERNEL_COMBINATION .

Parameter:

piCombination

A pointer to an integer value that receives the combination method.

HRESULT put_KernelCombination( [in ] int iCombination );

Sets the method for kernel combination as MV_KERNEL_COMBINATION .

Parameter:

iCombination

The combination method.

HRESULT get_NumOfKernelColumns( [out, retval] int *piColumns );

Returns the number of columns in the selected kernel.

Parameter:

piColumns

A pointer to an integer value that receives the number of columns.

HRESULT put_NumOfKernelColumns( [in ] int iColumns );

Sets the number of columns in the selected kernel.

Parameter:

iColumns

The desired number of columns.

HRESULT get_NumOfKernelRows( [out, retval] int *piRows );

Returns the number of rows in the selected kernel.

Parameter:

piRows

A pointer to an integer value that receives the number of rows.

HRESULT put_NumOfKernelRows( [in ] int iRows );

Sets the number of rows in the selected kernel.

Parameter:

iRows

The number of rows.

HRESULT GetKernelValue( [in ] int iColumn, [in ] int iRow, [out, retval ] int *piValue );

Returns the matrix value for the selected kernel using the position passed [iColumn, iRow].

Parameter:

	iColumn	Matrix column
	iRow	Matrix row
	piValue	A pointer to an integer value that receives the matrix value.

HRESULT SetKernelValue( [in ] int iColumn, [in ] int iRow, [in ] int iValue );

Sets the matrix value for the selected kernel at position [iColumn, iRow].

Parameter:

	iColumn	Matrix column
	iRow	Matrix row
	iValue	Matrix value

HRESULT get_XAnchor( [out, retval] int *piAnchor );

Returns the horizontal anchor of the selected kernel.

Parameter:

piAnchor

A pointer to an integer value that receives the horizontal anchor.

HRESULT put_XAnchor( [in ] int iAnchor );

Sets the horizontal anchor of the selected kernel.

Parameter:

iAnchor

The horizontal anchor.

HRESULT get_YAnchor( [out, retval] int *piAnchor );

Returns the vertical anchor of the selected kernel.

Parameter:

piAnchor

A pointer to an integer value that receives the vertical anchor.

HRESULT put_YAnchor( [in ] int iAnchor );

Sets the vertical anchor of the selected kernel.

Parameter:

iAnchor

The vertical anchor.

HRESULT get_RightShift( [out, retval] int *piShift );

Returns the current pixel right shift that is used to scale the convolution result of the current kernel.

Parameter:

piShift

A pointer to an integer value that receives the pixel right shift.

HRESULT put_RightShift( [in ] int iShift );

Sets the current pixel right shift that is used to scale the convolution result of the current kernel.

Parameter:

iShift

The pixel right shift.

Filter specific structures and enumerators

typedef enum _MV_KERNEL_COMBINATION
{
    MV_MV_COMBINATION_SUM= 0,
    MV_MV_COMBINATION_SUMSQ,
    MV_MV_COMBINATION_SUMSQROOT,
    MV_MV_COMBINATION_MAX,
    MV_MV_COMBINATION_MIN
} MV_KERNEL_COMBINATION;

Remarks

The following is an example sequence using the interface.

IMVConvolution *pIMVConvolution;

...

// Use two kernels
pIMVConvolution->put_NumOfKernels( 2 );

// Select kernel one
pIMVConvolution->put_SelectedKernel( 0 );

// Init kernel one
pIMVConvolution->put_NumOfKernelColumns( 3 );
pIMVConvolution->put_NumOfKernelRows( 3 );
pIMVConvolution->put_XAnchor( 1 );
pIMVConvolution->put_YAnchor( 1 );
pIMVConvolution->put_RightShift( 0 );

// Create vertical sobel matrix
// 1   2   1
// 0   0   0
// -1 -2 -1
// Column 0, Row 0
pIMVConvolution->SetKernelValue( 0, 0, 1 );
// Column 0, Row 1
pIMVConvolution->SetKernelValue( 0, 1, 0 );
// Column 0, Row 2
pIMVConvolution->SetKernelValue( 0, 2, -1 );

...

// Select kernel two
pIMVConvolution->put_SelectedKernel( 1 );

// Init kernel two
pIMVConvolution->put_NumOfKernelColumns( 3 );
pIMVConvolution->put_NumOfKernelRows( 3 );
pIMVConvolution->put_XAnchor( 1 );
pIMVConvolution->put_YAnchor( 1 );
pIMVConvolution->put_RightShift( 0 );

// Create horizontal sobel matrix
// 1   0 -1
// 2   0 -2
// 1   0 -1
// Column 0, Row 0
pIMVConvolution->SetKernelValue( 0, 0, 1 );
// Column 0, Row 1
pIMVConvolution->SetKernelValue( 0, 1, 2 );
// Column 0, Row 2
pIMVConvolution->SetKernelValue( 0, 2, 1 );

...

pIMVConvolution->put_KernelCombination( MV_MV_COMBINATION_SUM );