ImageDev

Pruning3d

Point detector removing spurs from a three-dimensional binary image.

Access to parameter description

For an introduction: This algorithm prunes the result of a skeletonization. It removes all object voxels having only one neighbor.
It can be applied either specifying a number of iterations or until convergence.
This filter can be used for removing terminal branches from a skeleton, also known as spurs.

The skeleton is very sensitive to small distortions on the edges of the objects, generating artifacts. The pruning algorithm eliminates these artifacts by thinning with the following structuring element until convergence or for a predefined number of iterations.

The skeleton is first detected, and then this algorithm performs a thinning transform with the following configuration and its 25 associated rotations: $$ \begin{array}{ccc} 0 & 0 & 0\\ 0 & \times & 0\\ 0 & 0 & 0 \end{array} ~~~~~~~~~~~~ \begin{array}{ccc} 0 & 0 & 0\\ 0 & 1 & 0\\ 0 & 0 & 0 \end{array} ~~~~~~~~~~~~ \begin{array}{ccc} 0 & 0 & 0\\ 0 & 0 & 0\\ 0 & 0 & 0 \end{array} $$ Where $\times$ means "don't care".

It is generally tedious to determine the number of iterations for the pruning and thinning until convergence removes all the skeletons except loops and branches intersecting the frame of the image in permissive mode.
The strict mode stops when an intersection or a right angle is encountered.

See also

Function Syntax

This function returns the outputBinaryImage output parameter. 
// Function prototype.
std::shared_ptr< iolink::ImageView >
pruning3d( std::shared_ptr< iolink::ImageView > inputBinaryImage,
           Pruning3d::PruningMode pruningMode,
           int32_t numberOfIterations,
           std::shared_ptr< iolink::ImageView > outputBinaryImage = NULL );
This function returns the outputBinaryImage output parameter. 
// Function prototype.
pruning_3d( input_binary_image,
            pruning_mode = Pruning3d.PruningMode.RIGOROUS,
            number_of_iterations = 1,
            output_binary_image = None )
This function returns the outputBinaryImage output parameter. 
// Function prototype.
public static IOLink.ImageView
Pruning3d( IOLink.ImageView inputBinaryImage,
           Pruning3d.PruningMode pruningMode = ImageDev.Pruning3d.PruningMode.RIGOROUS,
           Int32 numberOfIterations = 1,
           IOLink.ImageView outputBinaryImage = null );

Class Syntax

Parameters

Class Name Pruning3d

Parameter Name Description Type Supported Values Default Value
input
inputBinaryImage
The binary input image. Image Binary nullptr
input
pruningMode
The mode for removing end points.
RIGOROUS Each iteration removes only the end points having one neighbor. Using this mode, the pruning stops when an intersection or a right angle is encountered.
PERMISSIVE A skeletonization is reapplied between two iterations. Using this mode, only the closed-loops are kept.
Enumeration RIGOROUS
input
numberOfIterations
The number of iterations. If equal to 0, the algorithm is run until convergence. Int32 >=0 1
output
outputBinaryImage
The binary output image. Its size and type are forced to the same values as the input. Image nullptr

Object Examples

auto foam_sep = readVipImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "foam_sep.vip" );

Pruning3d pruning3dAlgo;
pruning3dAlgo.setInputBinaryImage( foam_sep );
pruning3dAlgo.setPruningMode( Pruning3d::PruningMode::RIGOROUS );
pruning3dAlgo.setNumberOfIterations( 1 );
pruning3dAlgo.execute();

std::cout << "outputBinaryImage:" << pruning3dAlgo.outputBinaryImage()->toString();

foam_sep = imagedev.read_vip_image(imagedev_data.get_image_path("foam_sep.vip"))

pruning_3d_algo = imagedev.Pruning3d()
pruning_3d_algo.input_binary_image = foam_sep
pruning_3d_algo.pruning_mode = imagedev.Pruning3d.RIGOROUS
pruning_3d_algo.number_of_iterations = 1
pruning_3d_algo.execute()

print( "output_binary_image:", str( pruning_3d_algo.output_binary_image ) )

ImageView foam_sep = Data.ReadVipImage( @"Data/images/foam_sep.vip" );

Pruning3d pruning3dAlgo = new Pruning3d
{
    inputBinaryImage = foam_sep,
    pruningMode = Pruning3d.PruningMode.RIGOROUS,
    numberOfIterations = 1
};
pruning3dAlgo.Execute();

Console.WriteLine( "outputBinaryImage:" + pruning3dAlgo.outputBinaryImage.ToString() );

Function Examples

auto foam_sep = readVipImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "foam_sep.vip" );

auto result = pruning3d( foam_sep, Pruning3d::PruningMode::RIGOROUS, 1 );

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

foam_sep = imagedev.read_vip_image(imagedev_data.get_image_path("foam_sep.vip"))

result = imagedev.pruning_3d( foam_sep, imagedev.Pruning3d.RIGOROUS, 1 )

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

ImageView foam_sep = Data.ReadVipImage( @"Data/images/foam_sep.vip" );

IOLink.ImageView result = Processing.Pruning3d( foam_sep, Pruning3d.PruningMode.RIGOROUS, 1 );

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