F_VN_CreateLowpassButterworthFilter

Creates a lowpass Butterworth filter, which can be applied to a frequency domain image by element-wise multiplication.

Syntax

Definition:

FUNCTION F_VN_CreateLowpassButterworthFilter : HRESULT
VAR_INPUT
    ipFilter         : Reference To  ITcVnImage;
    nWidth           : UDINT;
    nHeight          : UDINT;
    bDoublePrecision : BOOL;
    bOriginAtCenter  : BOOL;
    fCutoffDistance  : LREAL;
    nOrder           : UDINT;
    fScale           : LREAL;
    hrPrev           : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipFilter	Reference To ITcVnImage	Returns the created filter (1 channel of type REAL or LREAL, depending on bDoublePrecision. Non-zero interface pointers are reused.).
nWidth	UDINT	Filter width (even, >= 2, must match the width of the image it is applied to)
nHeight	UDINT	Filter height (even, >= 2, must match the height of the image it is applied to)
bDoublePrecision	BOOL	If true, the filter is generated with double precision (LREAL) instead of single precision (REAL).
bOriginAtCenter	BOOL	If true, the filter origin is shifted to the image center.
fCutoffDistance	LREAL	The cutoff distance of the Butterworth filter (> 0).
nOrder	UDINT	The order of the Butterworth filter (> 0).
fScale	LREAL	The scale factor of the Butterworth filter denominator term (> 0, e.g. 0.414 or 1.0).
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

Return value

HRESULT

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