BilateralFilter2d

Applies a two-dimensional edge-preserving smoothing filter.

Access to parameter description

For an introduction to image filters: see Images Filtering.

This algorithm is an edge-preserving smoothing filter. The intensity value at each pixel in an image is replaced by a weighted average of intensity values from nearby pixels. Crucially, the weights depend on the distance in color space from the considered pixel.
It preserves sharp edges by systematically excluding pixels across discontinuities from consideration:

$O(i,j)=\frac{1}{K(i,j)}\sum_{l=-\frac{n_x}{2}}^{\frac{n_x}{2}} \sum_{m=-\frac{n_y}{2}}^{\frac{n_y}{2}}e^{_\frac{(I(i,j)-I(l,m))^2}{h^2}} I(l,m)$
Where

$h$ is a weighting similarity factor and

$K$ is a local normalisation factor given by:

$K(i,j)=\sum_{l=-\frac{n_x}{2}}^{\frac{n_x}{2}} \sum_{m=-\frac{n_y}{2}}^{\frac{n_y}{2}}e^{_\frac{(I(i,j)-I(l,m))^2}{h^2}} I(l,m)$
The greater

$h$ is, the stronger the blur.

A filter mode parameter allows this algorithm to switch to the SUSAN filter (Smallest Univalue Segment Assimilating Nucleus).
The SUSAN filter reproduces bilateral filter behavior simply by excluding the central pixel of computation. This filter gives better results in the case of impulse noise.

Reference:
C.Tomasi, R.Manduchi. "Bilateral Filtering for Gray and Color Images". Sixth International Conference on Computer Vision (IEEE Cat. No.98CH36271), Bombay, India, pp. 839-846, 1998.

See also

Function Syntax

This function returns outputImage.

// Function prototype
std::shared_ptr< iolink::ImageView >
bilateralFilter2d( std::shared_ptr< iolink::ImageView > inputImage,
                   int32_t kernelSizeX,
                   int32_t kernelSizeY,
                   double similarity,
                   BilateralFilter2d::FilterMode filterMode,
                   std::shared_ptr< iolink::ImageView > outputImage = nullptr );

This function returns outputImage.

// Function prototype.
bilateral_filter_2d(input_image: idt.ImageType,
                    kernel_size_x: int = 3,
                    kernel_size_y: int = 3,
                    similarity: float = 20,
                    filter_mode: BilateralFilter2d.FilterMode = BilateralFilter2d.FilterMode.BILATERAL,
                    output_image: idt.ImageType = None) -> idt.ImageType

This function returns outputImage.

// Function prototype.
public static IOLink.ImageView
BilateralFilter2d( IOLink.ImageView inputImage,
                   Int32 kernelSizeX = 3,
                   Int32 kernelSizeY = 3,
                   double similarity = 20,
                   BilateralFilter2d.FilterMode filterMode = ImageDev.BilateralFilter2d.FilterMode.BILATERAL,
                   IOLink.ImageView outputImage = null );

Class Syntax

// Command constructor.
BilateralFilter2d();

/// Gets the inputImage parameter.
/// The input image.
std::shared_ptr< iolink::ImageView > inputImage() const;
/// Sets the inputImage parameter.
/// The input image.
void setInputImage( std::shared_ptr< iolink::ImageView > inputImage );

/// Gets the kernelSizeX parameter.
/// The horizontal kernel size in pixels (odd value).
int32_t kernelSizeX() const;
/// Sets the kernelSizeX parameter.
/// The horizontal kernel size in pixels (odd value).
void setKernelSizeX( const int32_t& kernelSizeX );

/// Gets the kernelSizeY parameter.
/// The vertical kernel size in pixels (odd value).
int32_t kernelSizeY() const;
/// Sets the kernelSizeY parameter.
/// The vertical kernel size in pixels (odd value).
void setKernelSizeY( const int32_t& kernelSizeY );

/// Gets the similarity parameter.
/// The weighting similarity factor (must be a positive value).
double similarity() const;
/// Sets the similarity parameter.
/// The weighting similarity factor (must be a positive value).
void setSimilarity( const double& similarity );

/// Gets the filterMode parameter.
/// The way to consider the central pixel.
BilateralFilter2d::FilterMode filterMode() const;
/// Sets the filterMode parameter.
/// The way to consider the central pixel.
void setFilterMode( const BilateralFilter2d::FilterMode& filterMode );

/// Gets the outputImage parameter.
/// The output image. Its dimensions, type, and calibration are forced to the same values as the input.
std::shared_ptr< iolink::ImageView > outputImage() const;
/// Sets the outputImage parameter.
/// The output image. Its dimensions, type, and calibration are forced to the same values as the input.
void setOutputImage( std::shared_ptr< iolink::ImageView > outputImage );


// Method to launch the command.
void execute();

# Property of the inputImage parameter.
BilateralFilter2d.input_image
# Property of the kernelSizeX parameter.
BilateralFilter2d.kernel_size_x
# Property of the kernelSizeY parameter.
BilateralFilter2d.kernel_size_y
# Property of the similarity parameter.
BilateralFilter2d.similarity
# Property of the filterMode parameter.
BilateralFilter2d.filter_mode
# Property of the outputImage parameter.
BilateralFilter2d.output_image

// Method to launch the command.
execute()

// Command constructor.
BilateralFilter2d()

// Property of the inputImage parameter.
BilateralFilter2d.inputImage
// Property of the kernelSizeX parameter.
BilateralFilter2d.kernelSizeX
// Property of the kernelSizeY parameter.
BilateralFilter2d.kernelSizeY
// Property of the similarity parameter.
BilateralFilter2d.similarity
// Property of the filterMode parameter.
BilateralFilter2d.filterMode
// Property of the outputImage parameter.
BilateralFilter2d.outputImage

// Method to launch the command.
Execute()

Parameters

Parameter Name

Description

Type

Supported Values

Default Value

inputImage

The input image.

Image

Binary, Label, Grayscale or Multispectral

nullptr

kernelSizeX

The horizontal kernel size in pixels (odd value).

Int32

[3, 100]

kernelSizeY

The vertical kernel size in pixels (odd value).

Int32

[3, 100]

similarity

The weighting similarity factor (must be a positive value).

Float64

filterMode

The way to consider the central pixel.

BILATERAL	This mode corresponds to the standard bilateral filter (uses the central point).
SUSAN	This mode corresponds to the SUSAN filter (does not use the central point).

Enumeration

BILATERAL

outputImage

The output image. Its dimensions, type, and calibration are forced to the same values as the input.

Image

nullptr

Object Examples

auto polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

BilateralFilter2d bilateralFilter2dAlgo;
bilateralFilter2dAlgo.setInputImage( polystyrene );
bilateralFilter2dAlgo.setKernelSizeX( 3 );
bilateralFilter2dAlgo.setKernelSizeY( 3 );
bilateralFilter2dAlgo.setSimilarity( 20.0 );
bilateralFilter2dAlgo.setFilterMode( BilateralFilter2d::FilterMode::BILATERAL );
bilateralFilter2dAlgo.execute();

std::cout << "outputImage:" << bilateralFilter2dAlgo.outputImage()->toString();

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))

bilateral_filter_2d_algo = imagedev.BilateralFilter2d()
bilateral_filter_2d_algo.input_image = polystyrene
bilateral_filter_2d_algo.kernel_size_x = 3
bilateral_filter_2d_algo.kernel_size_y = 3
bilateral_filter_2d_algo.similarity = 20.0
bilateral_filter_2d_algo.filter_mode = imagedev.BilateralFilter2d.BILATERAL
bilateral_filter_2d_algo.execute()

print("output_image:", str(bilateral_filter_2d_algo.output_image))

ImageView polystyrene = ViewIO.ReadImage( @"Data/images/polystyrene.tif" );

BilateralFilter2d bilateralFilter2dAlgo = new BilateralFilter2d
{
    inputImage = polystyrene,
    kernelSizeX = 3,
    kernelSizeY = 3,
    similarity = 20.0,
    filterMode = BilateralFilter2d.FilterMode.BILATERAL
};
bilateralFilter2dAlgo.Execute();

Console.WriteLine( "outputImage:" + bilateralFilter2dAlgo.outputImage.ToString() );

Function Examples

auto polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

auto result = bilateralFilter2d( polystyrene, 3, 3, 20.0, BilateralFilter2d::FilterMode::BILATERAL );

std::cout << "outputImage:" << result->toString();

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))

result = imagedev.bilateral_filter_2d(polystyrene, 3, 3, 20.0, imagedev.BilateralFilter2d.BILATERAL)

print("output_image:", str(result))

ImageView polystyrene = ViewIO.ReadImage( @"Data/images/polystyrene.tif" );

IOLink.ImageView result = Processing.BilateralFilter2d( polystyrene, 3, 3, 20.0, BilateralFilter2d.FilterMode.BILATERAL );

Console.WriteLine( "outputImage:" + result.ToString() );

BilateralFilter2d

- Function Syntax

+ Class Syntax

Parameters

Object Examples

Function Examples

Function Syntax

Class Syntax