F_VN_CustomFilter

Syntax

Definition:

FUNCTION F_VN_CustomFilter : HRESULT
VAR_INPUT
    ipSrcImage  : ITcVnImage;
    ipDestImage : Reference To  ITcVnImage;
    eDestDepth  : ETcVnElementType;
END_VAR
VAR_IN_OUT
    stKernel    : TcVnMatrix;
END_VAR
VAR_INPUT
    hrPrev      : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipSrcImage	ITcVnImage	Source image
ipDestImage	Reference To ITcVnImage	Destination image (An appropriate destination image will be created if required.)
eDestDepth	ETcVnElementType	Destination image depth
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
stKernel	TcVnMatrix	Custom filter kernel with values of type REAL or LREAL

Return value

HRESULT

Further information

The function F_VN_CustomFilter applies a user-defined filter to the input image. The filter kernel is defined by a matrix. This matrix is folded with the image.

Parameter

Input image

The input image ipSrcImage may have any available format.

Result image

The result image ipDestImage has the same format as the input image ipSrcImage.

Result depth

The result depth eDestDepth defines which element type the result image ipDestImage has. A larger element type can display more information.

Filter kernel

The user-defined filter kernel stKernel is transferred as a matrix. Permitted element types of the matrix are TCVN_ET_REAL and TCVN_ET_LREAL. A corresponding matrix of the type TcVnMatrix can be created with the aid of the function F_VN_InitMatrixStruct.

Expert parameters

The expert version F_VN_CustomFilterExp contains additional parameters.

Application

hr := F_VN_InitMatrixStruct(
    pSrcBuffer      := ADR(aMatrixArray7x7),
    stDestMatrix    := stKernelMatrix,
    nRows           := 7,
    nCols           := 7,
    eElementType    := TCVN_ET_REAL,
    hrPrev          := hr
);

hr := F_VN_CustomFilter(
    ipSrcImage  :=  ipImageIn,
    ipDestImage :=  ipImageRes,
    eDestDepth  :=  TCVN_ET_USINT,
    stKernel    :=  stKernelMatrix,
    hrPrev      :=  hr
);

The unprocessed original image (1^st row) already exhibits fine structures on the surface of the gear wheels in the detail. In order to illustrate the effects of the filters, additional disturbances were added to the original image by Gauss noise (2^nd row) and salt-and-pepper noise (3^rd row). An average filter is implemented as an example; a more detailed description can be found in the sample for the Blur filter:

Original images	Result images: Mean filter

Samples

Blur filter
User-defined filters

Required License

TC3 Vision Base

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.54 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision