ImageDev

Despeckle2d

Smooths a two-dimensional image by replacing any aberrant pixel values by their neighbors mean value.

Access to parameter description

For an introduction to image filters: see Images Filtering.

For each pixel of the input image, mean $\mu$ and standard deviation $\sigma$ values of a rectangular neighbor window are computed.
The output image value is then given by: $$ O(i,j)=\left\{\begin{array}{ll} \mu(i,j) & ~ \mbox{if} ~ \lambda \times |I(i,j)-\mu(i,j)| > \sigma(i,j)\\ I(i,j) & ~ \mbox{otherwise} \end{array}\right. $$
Where $\lambda$ is a user-defined threshold factor on the distance of the current pixel gray level to the mean of its neighbors, relative to their standard deviation.
The greater $\lambda$ is, the stronger the blur.

This filter gives good results in the case of impulse noise.

See also

Function Syntax

This function returns outputImage. 
// Function prototype
std::shared_ptr< iolink::ImageView >
despeckle2d( std::shared_ptr< iolink::ImageView > inputImage,
             int32_t kernelSizeX,
             int32_t kernelSizeY,
             double thresholdFactor,
             std::shared_ptr< iolink::ImageView > outputImage = nullptr );
This function returns outputImage. 
// Function prototype.
despeckle_2d(input_image: idt.ImageType,
             kernel_size_x: int = 3,
             kernel_size_y: int = 3,
             threshold_factor: float = 1,
             output_image: idt.ImageType = None) -> idt.ImageType
This function returns outputImage. 
// Function prototype.
public static IOLink.ImageView
Despeckle2d( IOLink.ImageView inputImage,
             Int32 kernelSizeX = 3,
             Int32 kernelSizeY = 3,
             double thresholdFactor = 1,
             IOLink.ImageView outputImage = null );

Class Syntax

Parameters

Parameter Name Description Type Supported Values Default Value
input
inputImage
The input image. Image Binary, Label, Grayscale or Multispectral nullptr
input
kernelSizeX
Horizontal kernel size in pixels (odd value). Int32 [3, 100] 3
input
kernelSizeY
Vertical kernel size in pixels (odd value). Int32 [3, 100] 3
input
thresholdFactor
The standard deviation threshold factor (must be a positive value). Float64 >0 1
output
outputImage
The output image. Its dimensions, type, and calibration are forced to the same values as the input. Image nullptr
Parameter Name Description Type Supported Values Default Value
input
input_image
The input image. image Binary, Label, Grayscale or Multispectral None
input
kernel_size_x
Horizontal kernel size in pixels (odd value). int32 [3, 100] 3
input
kernel_size_y
Vertical kernel size in pixels (odd value). int32 [3, 100] 3
input
threshold_factor
The standard deviation threshold factor (must be a positive value). float64 >0 1
output
output_image
The output image. Its dimensions, type, and calibration are forced to the same values as the input. image None
Parameter Name Description Type Supported Values Default Value
input
inputImage
The input image. Image Binary, Label, Grayscale or Multispectral null
input
kernelSizeX
Horizontal kernel size in pixels (odd value). Int32 [3, 100] 3
input
kernelSizeY
Vertical kernel size in pixels (odd value). Int32 [3, 100] 3
input
thresholdFactor
The standard deviation threshold factor (must be a positive value). Float64 >0 1
output
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" );

Despeckle2d despeckle2dAlgo;
despeckle2dAlgo.setInputImage( polystyrene );
despeckle2dAlgo.setKernelSizeX( 3 );
despeckle2dAlgo.setKernelSizeY( 3 );
despeckle2dAlgo.setThresholdFactor( 1.0 );
despeckle2dAlgo.execute();

std::cout << "outputImage:" << despeckle2dAlgo.outputImage()->toString();

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

despeckle_2d_algo = imagedev.Despeckle2d()
despeckle_2d_algo.input_image = polystyrene
despeckle_2d_algo.kernel_size_x = 3
despeckle_2d_algo.kernel_size_y = 3
despeckle_2d_algo.threshold_factor = 1.0
despeckle_2d_algo.execute()

print("output_image:", str(despeckle_2d_algo.output_image))

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

Despeckle2d despeckle2dAlgo = new Despeckle2d
{
    inputImage = polystyrene,
    kernelSizeX = 3,
    kernelSizeY = 3,
    thresholdFactor = 1.0
};
despeckle2dAlgo.Execute();

Console.WriteLine( "outputImage:" + despeckle2dAlgo.outputImage.ToString() );

Function Examples

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

auto result = despeckle2d( polystyrene, 3, 3, 1.0 );

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

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

result = imagedev.despeckle_2d(polystyrene, 3, 3, 1.0)

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

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

IOLink.ImageView result = Processing.Despeckle2d( polystyrene, 3, 3, 1.0 );

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