F_VN_GaussianFilter
Apply a Gaussian filter to smooth the image.
Can use available TwinCAT Job Tasks for executing parallel code regions.
Syntax
Definition:
FUNCTION F_VN_GaussianFilter : HRESULT
VAR_INPUT
ipSrcImage : ITcVnImage;
ipDestImage : Reference To ITcVnImage;
nFilterWidth : UDINT;
nFilterHeight : UDINT;
hrPrev : HRESULT;
END_VAR
Inputs
|
Name |
Type |
Description |
|---|---|---|
|
ipSrcImage |
Source image | |
|
ipDestImage |
Reference To ITcVnImage |
Destination image (An appropriate destination image will be created if required.) |
|
nFilterWidth |
UDINT |
Filter width in pixels (1, 3, 5, 7, ...) |
|
nFilterHeight |
UDINT |
Filter height in pixels (1, 3, 5, 7, ...) |
|
hrPrev |
HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.) |
Return valueFurther information
The function F_VN_GaussianFilter applies a Gaussian filter to the input image.
Algorithm
The Gaussian filter is often used in image processing to reduce noise or smooth an image. Each pixel is replaced by the weighted average of its environment, removing smaller details but preserving larger ones. The larger the filter, the more smoothed the image will be (and therefore appears more blurred).
Parameter
Input image
The input image ipSrcImage may have any available format.
Result image
The result image ipDestImage is given the same format as the input image ipSrcImage.
Filter size
The size of the Gauss filter is described in the X direction by nFilterWidth and in the Y direction by nFilterHeight. The size specifications must be odd numbers, as there must always be a central pixel.
Expert parameters
The expert version F_VN_GaussianFilterExp contains additional parameters.
Application
hr := F_VN_GaussianFilter(
ipSrcImage := ipImageIn,
ipDestImage := ipImageRes,
nFilterWidth := 7,
nFilterHeight := 7,
hrPrev := hr
);
The unprocessed original image (1st 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 (2nd row) and salt-and-pepper noise (3rd row).
Original images | Result images |
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Samples
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 |