F_VN_BilateralFilter
Apply a Bilateral filter to smooth the image but preserve edges.
Can use available TwinCAT Job Tasks for executing parallel code regions.
Syntax
Definition:
FUNCTION F_VN_BilateralFilter : HRESULT
VAR_INPUT
ipSrcImage : ITcVnImage;
ipDestImage : Reference To ITcVnImage;
nDiameter : DINT;
fSigmaColor : LREAL;
fSigmaSpace : LREAL;
hrPrev : HRESULT;
END_VAR
Inputs
|
Name |
Type |
Description |
|---|---|---|
|
ipSrcImage |
Source image | |
|
ipDestImage |
Reference To ITcVnImage |
Destination image (Must be different from ipSrcImage! An appropriate destination image will be created if required.) |
|
nDiameter |
DINT |
Diameter of the pixel neighborhood used for filtering (e.g. 5, 7, 9). If <= 0, it is automatically chosen dependend on fSigmaSpace. |
|
fSigmaColor |
LREAL |
Sigma used for color space filtering (> 0). A larger value means that farther colors are mixed together. |
|
fSigmaSpace |
LREAL |
Sigma used for coordinate space filtering (> 0). A larger value means that farther pixels can influence each other. |
|
hrPrev |
HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.) |
Return valueFurther information
The function F_VN_BilateralFilter applies a bilateral filter to the original image. The filter smooths the image and reduces noise while retaining the edges in the image.
Parameter
Original image
The original image ipSrcImage must be of the element type TCVN_ET_USINT or a floating point type and have 1 or 3 channels.
Result image
The result image ipDestImage must be a different interface pointer to the original image ipSrcImage!
Filter diameter
The filter diameter nDiameter determines the size of a filter area. An odd number is expected. If nDiameter = 0, then the filter diameter is automatically calculated on the basis of fSigmaSpace.
Color area
This value may not be 0.
Room area
This value may not be 0.
Expert parameters
Further parameters can be found in the expert version F_VN_BilateralFilterExp.
Application
An application of this function can look like this, for example:
hr := F_VN_BilateralFilter(
ipSrcImage := ipImage,
ipDestImage := ipImageRes,
nDiameter := nDiameter,
fSigmaColor := fSigmaColor,
fSigmaSpace := fSigmaSpace,
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: Diameter = 7 Sigma = 100 |
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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 |