CurvatureDrivenDiffusion

Smooths a two-dimensional image using an advanced local edge analysis technique.

Access to parameter description

For an introduction to image filters: see Images Filtering.

This algorithm smooths an image with respect to its edges.
The algorithm is ruled by three main parameters: number of iterations, sharpness, and anisotropy.

Figure 1. Curvature-Driven diffusion on a noisy image with default parameters (10 iterations, sharpness = 0.9 and anisotropy = 0.6)

The number of iterations must be specified and suitable to reach convergence. Practically, a default value of 10 iterations achieves good results in most of the cases.
The sharpness parameter controls the amplitude of smoothing along the edge direction. A small sharpness value generates a strong global smoothing.

Figure 2. Influence of sharpness parameter on curvature-driven diffusion process: (left) Sharpness = 0.1, (right) Sharpness = 2.0

The anisotropy parameter controls the local curvature-driven diffusion along the gradient direction (direction orthogonal to the edge). A low value for anisotropy parameter results in a stronger local smoothing of edges.

Figure 3. Influence of anisotropy parameter on curvature-driven diffusion process: (left) Anisotropy = 0.3, (right) Anisotropy = 0.9
Reference:
J.Weickert. "Anisotropic Diffusion in Image Processing". B.G. Teubber Verlag, Stuttgart, 1998.

See also

Function Syntax

This function returns outputImage.

// Function prototype
std::shared_ptr< iolink::ImageView >
curvatureDrivenDiffusion( std::shared_ptr< iolink::ImageView > inputImage,
                          std::shared_ptr< iolink::ImageView > inputMaskImage,
                          int32_t numberOfIterations,
                          double sharpnessFactor,
                          double anisotropyFactor,
                          std::shared_ptr< iolink::ImageView > outputImage = nullptr );

This function returns outputImage.

// Function prototype.
curvature_driven_diffusion(input_image: idt.ImageType,
                           input_mask_image: idt.ImageType,
                           number_of_iterations: int = 10,
                           sharpness_factor: float = 0.9,
                           anisotropy_factor: float = 0.6,
                           output_image: idt.ImageType = None) -> idt.ImageType

This function returns outputImage.

// Function prototype.
public static IOLink.ImageView
CurvatureDrivenDiffusion( IOLink.ImageView inputImage,
                          IOLink.ImageView inputMaskImage,
                          Int32 numberOfIterations = 10,
                          double sharpnessFactor = 0.9,
                          double anisotropyFactor = 0.6,
                          IOLink.ImageView outputImage = null );

Class Syntax

// Command constructor.
CurvatureDrivenDiffusion();

/// 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 inputMaskImage parameter.
/// The optional binary mask defining area to process into input image (null to process the whole image). It must have same dimensions as the input image and cannot be null.
std::shared_ptr< iolink::ImageView > inputMaskImage() const;
/// Sets the inputMaskImage parameter.
/// The optional binary mask defining area to process into input image (null to process the whole image). It must have same dimensions as the input image and cannot be null.
void setInputMaskImage( std::shared_ptr< iolink::ImageView > inputMaskImage );

/// Gets the numberOfIterations parameter.
/// The number of iterations of the curvature-driven diffusion process (must be a positive integer).
int32_t numberOfIterations() const;
/// Sets the numberOfIterations parameter.
/// The number of iterations of the curvature-driven diffusion process (must be a positive integer).
void setNumberOfIterations( const int32_t& numberOfIterations );

/// Gets the sharpnessFactor parameter.
/// The edge preserving factor.
double sharpnessFactor() const;
/// Sets the sharpnessFactor parameter.
/// The edge preserving factor.
void setSharpnessFactor( const double& sharpnessFactor );

/// Gets the anisotropyFactor parameter.
/// The curvature-driven factor (value within ]0, 1[).
double anisotropyFactor() const;
/// Sets the anisotropyFactor parameter.
/// The curvature-driven factor (value within ]0, 1[).
void setAnisotropyFactor( const double& anisotropyFactor );

/// 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.
CurvatureDrivenDiffusion.input_image
# Property of the inputMaskImage parameter.
CurvatureDrivenDiffusion.input_mask_image
# Property of the numberOfIterations parameter.
CurvatureDrivenDiffusion.number_of_iterations
# Property of the sharpnessFactor parameter.
CurvatureDrivenDiffusion.sharpness_factor
# Property of the anisotropyFactor parameter.
CurvatureDrivenDiffusion.anisotropy_factor
# Property of the outputImage parameter.
CurvatureDrivenDiffusion.output_image

// Method to launch the command.
execute()

// Command constructor.
CurvatureDrivenDiffusion()

// Property of the inputImage parameter.
CurvatureDrivenDiffusion.inputImage
// Property of the inputMaskImage parameter.
CurvatureDrivenDiffusion.inputMaskImage
// Property of the numberOfIterations parameter.
CurvatureDrivenDiffusion.numberOfIterations
// Property of the sharpnessFactor parameter.
CurvatureDrivenDiffusion.sharpnessFactor
// Property of the anisotropyFactor parameter.
CurvatureDrivenDiffusion.anisotropyFactor
// Property of the outputImage parameter.
CurvatureDrivenDiffusion.outputImage

// Method to launch the command.
Execute()

Parameters

	Description	Type	Supported Values	Default Value
inputImage	The input image.	Image	Binary, Label, Grayscale or Multispectral	nullptr
inputMaskImage	The optional binary mask defining area to process into input image (null to process the whole image). It must have same dimensions as the input image and cannot be null.	Image	Binary	nullptr
numberOfIterations	The number of iterations of the curvature-driven diffusion process (must be a positive integer).	Int32	>=1	10
sharpnessFactor	The edge preserving factor.	Float64	>=0	0.9
anisotropyFactor	The curvature-driven factor (value within ]0, 1[).	Float64	[0, 0.99999]	0.6
outputImage	The output image. Its dimensions, type, and calibration are forced to the same values as the input.	Image		nullptr

	Description	Type	Supported Values	Default Value
input_image	The input image.	image	Binary, Label, Grayscale or Multispectral	None
input_mask_image	The optional binary mask defining area to process into input image (null to process the whole image). It must have same dimensions as the input image and cannot be null.	image	Binary	None
number_of_iterations	The number of iterations of the curvature-driven diffusion process (must be a positive integer).	int32	>=1	10
sharpness_factor	The edge preserving factor.	float64	>=0	0.9
anisotropy_factor	The curvature-driven factor (value within ]0, 1[).	float64	[0, 0.99999]	0.6
output_image	The output image. Its dimensions, type, and calibration are forced to the same values as the input.	image		None

	Description	Type	Supported Values	Default Value
inputImage	The input image.	Image	Binary, Label, Grayscale or Multispectral	null
inputMaskImage	The optional binary mask defining area to process into input image (null to process the whole image). It must have same dimensions as the input image and cannot be null.	Image	Binary	null
numberOfIterations	The number of iterations of the curvature-driven diffusion process (must be a positive integer).	Int32	>=1	10
sharpnessFactor	The edge preserving factor.	Float64	>=0	0.9
anisotropyFactor	The curvature-driven factor (value within ]0, 1[).	Float64	[0, 0.99999]	0.6
outputImage	The output image. Its dimensions, type, and calibration are forced to the same values as the input.	Image		null

Object Examples

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

CurvatureDrivenDiffusion curvatureDrivenDiffusionAlgo;
curvatureDrivenDiffusionAlgo.setInputImage( polystyrene );
curvatureDrivenDiffusionAlgo.setInputMaskImage( polystyrene_sep );
curvatureDrivenDiffusionAlgo.setNumberOfIterations( 3 );
curvatureDrivenDiffusionAlgo.setSharpnessFactor( 0.9 );
curvatureDrivenDiffusionAlgo.setAnisotropyFactor( 0.6 );
curvatureDrivenDiffusionAlgo.execute();

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

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))
polystyrene_sep = imagedev.read_vip_image(imagedev_data.get_image_path("polystyrene_sep.vip"))

curvature_driven_diffusion_algo = imagedev.CurvatureDrivenDiffusion()
curvature_driven_diffusion_algo.input_image = polystyrene
curvature_driven_diffusion_algo.input_mask_image = polystyrene_sep
curvature_driven_diffusion_algo.number_of_iterations = 3
curvature_driven_diffusion_algo.sharpness_factor = 0.9
curvature_driven_diffusion_algo.anisotropy_factor = 0.6
curvature_driven_diffusion_algo.execute()

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

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

CurvatureDrivenDiffusion curvatureDrivenDiffusionAlgo = new CurvatureDrivenDiffusion
{
    inputImage = polystyrene,
    inputMaskImage = polystyrene_sep,
    numberOfIterations = 3,
    sharpnessFactor = 0.9,
    anisotropyFactor = 0.6
};
curvatureDrivenDiffusionAlgo.Execute();

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

Function Examples

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

auto result = curvatureDrivenDiffusion( polystyrene, polystyrene_sep, 3, 0.9, 0.6 );

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

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))
polystyrene_sep = imagedev.read_vip_image(imagedev_data.get_image_path("polystyrene_sep.vip"))

result = imagedev.curvature_driven_diffusion(polystyrene, polystyrene_sep, 3, 0.9, 0.6)

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

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

IOLink.ImageView result = Processing.CurvatureDrivenDiffusion( polystyrene, polystyrene_sep, 3, 0.9, 0.6 );

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

CurvatureDrivenDiffusion

- Function Syntax

+ Class Syntax

Parameters

Object Examples

Function Examples

Function Syntax

Class Syntax