F_VN_SobelFilterExp

Syntax

Definition:

FUNCTION F_VN_SobelFilterExp : HRESULT
VAR_INPUT
    ipSrcImage  : ITcVnImage;
    ipDestImage : Reference To  ITcVnImage;
    eDestDepth  : ETcVnElementType;
    nXOrder     : UDINT;
    nYOrder     : UDINT;
    nKernelSize : UDINT;
    fScale      : LREAL;
    fDelta      : LREAL;
    eBorderType : ETcVnBorderInterpolationMethod;
    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
nXOrder	UDINT	Order of the x-derivative (must be < nKernelSize)
nYOrder	UDINT	Order of the y-derivative (must be < nKernelSize)
nKernelSize	UDINT	Size of the extended Sobel kernel (3, 5, 7, ..., 31)
fScale	LREAL	Scale factor for the computed derivative values
fDelta	LREAL	Delta value that is added to the results prior to storing them in dest
eBorderType	ETcVnBorderInterpolationMethod	Image border handling
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

Return value

HRESULT

Further information

The function F_VN_SobelFilterExp is the expert version of F_VN_SobelFilter. It contains additional parameters.

Parameter

Original image

The original image ipSrcImage can have any format.

Result image

The result image ipDestImage returns the filter result and has the same format as the original 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.

Derivative order

The derivative orders nXOrder and nYOrder define which derivative in the X and Y direction is to be used to create the filter.

Kernel size

The size nKernelSize of the Sobel kernel determines how large the area is that influences the result value of a pixel.

Scaling

The result of the Sobel operation is multiplied by the scaling factor fScale.

Delta

The constant delta fDelta is added to the result of the Sobel operation after scaling with fScale.

Border extrapolation

The method of border extrapolation eBorderType defines how non-existent pixels are extrapolated beyond the image border in order to calculate the filter values at the image borders. For further details, see ETcVnBorderInterpolationMethod.

Application

hr := F_VN_SobelFilterExp(
    ipSrcImage  :=  ipImageIn,
    ipDestImage :=  ipImageRes,
    eDestDepth  :=  TCVN_ET_USINT,
    nXOrder     :=  1,
    nYOrder     :=  1,
    nKernelSize :=  3,
    fScale      :=  1,
    fDelta      :=  0,
    eBorderType :=  TCVN_BIM_DEFAULT,
    hrPrev      :=  hr,
);