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FIL.SmoothImage_Bilateral

Smooths an image while preserving sharp edges.

Namespace:FilNet
Assembly:FIL.NET.dll

Syntax

C++
C#
 
public static void SmoothImage_Bilateral
(
	FilNet.Image inImage,
	float inDistanceSigma,
	float inColorSigma,
	FilNet.BilateralSamplingMethod inSamplingMethod,
	int inIterationCount,
	FilNet.Image outImage
)

Parameters

Name Type Range Default Description
inImageFilNet.ImageInput image.
inDistanceSigmafloat<0.0f, 128.0f>5.0fSigma used when calculating the gaussian difference two pixel positions. Default value: 5.0f.
inColorSigmafloat<0.0f, INF>35.0fSigma used when calculating the gaussian difference between two colors. Default value: 35.0f.
inSamplingMethodFilNet.BilateralSamplingMethodPoissonWhether to use a naive (full) or a subsampling method. Default value: Poisson.
inIterationCountint<1, INF>1Determines how many times the bilateral filter will be run. Default value: 1.
outImageFilNet.ImageOutput image.

Description

The bilateral filter is a low pass filtering algorithm weighting pixels not just in the spatial domain (which is what the gaussian filter does) but also in the color domain. This allows the filter to consider only the pixels that are both nearby and similar in color. The resulting image is smoothed but sharp edges are maintained.

A different image can be used for color distance calculations if the inEdgesImage parameter is set. This allows to transfer edges from other images or preserve edges only for part of an image.

The filter can be run in a iterative mode. When inIterationCount is set to a value greater than 1 the filter runs inIterationCount times using the result from the previous iteration as the edges image in the next.

The algorithm is computationally complex so, if high accuracy is not needed, Poisson Disk subsampling can be used to significantly speed up the algorithms execution time with minimal looses in quality.

Examples

Example input image

Output image with distance sigma set to 5 and color sigma set to 35

Output image with distance sigma set to 10 and color sigma set to 35

Edges image that is grey everywhere outside of a circle and the resulting output image.

Edges image which is different from the input image and the resulting output image.

Output image with distance sigma set to 5 and color sigma set to 35 after one iteration

Output image with distance sigma set to 5 and color sigma set to 35 after three iterations

Remarks

The inDistanceSigma parameter behaves similarly to standard deviation in the gaussian filter.

Higher values of inColorSigma allow the filter to blend pixel that differ more in terms of color.

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Hardware acceleration settings may be manipulated with Settings class.

Errors

List of possible exceptions:

Error type Description
DomainError Image and edges image must be of the same size in SmoothImage_Bilateral.
DomainError Image and edges image must be of the same type in SmoothImage_Bilateral.
DomainError Image and edges image must have the same depth in SmoothImage_Bilateral.
DomainError Region exceeds an input image in SmoothImage_Bilateral.

Function Overrides

See also