ImageDev

Skeleton

Computes the morphological skeleton of objects contained in a binary image.

Access to parameter description

For an introduction: The skeleton of a set $X$ is the line made up of those points for which the distance to the boundary of the set is reached by at least two points.

Imagining that the set $X$ is a dry herb prairie which starts to burn from all the points of its boundary, the skeleton is the line where the fires meet. Using the same analogy, the quench function can be defined as the time for the fire to reach this line.

<b> Figure 1.</b> Sq(X) is the quench function
Figure 1. Sq(X) is the quench function

<b> Figure 2.</b> Some shapes and their skeletons
Figure 2. Some shapes and their skeletons

This algorithm performs a sequential homotopic thinning. The input image is iteratively thinned by an homotopic structuring element until idempotence. This structuring element is the L configuration of Golay's alphabet and its 8 associated rotations: $$ \begin{array}{ccc} 1 & 1 & 1\\ \times & 1 & \times\\ 0 & 0 & 0 \end{array} $$ Where $\times$ means "don't care".

Note: This algorithm is described here in 2D but also can be launched on 3D images. Nevertheless, the skeleton definition given above is not always verified in the 3D case. Indeed the 3D skeleton is not systematically well centered. The Centerline3d algorithm can be used to get a more centered 3D skeleton.

See also

Function Syntax

This function returns outputBinaryImage. 
// Function prototype
std::shared_ptr< iolink::ImageView >
skeleton( std::shared_ptr< iolink::ImageView > inputBinaryImage, std::shared_ptr< iolink::ImageView > outputBinaryImage = NULL );
This function returns outputBinaryImage. 
// Function prototype.
skeleton( input_binary_image, output_binary_image = None )
This function returns outputBinaryImage. 
// Function prototype.
public static IOLink.ImageView
Skeleton( IOLink.ImageView inputBinaryImage, IOLink.ImageView outputBinaryImage = null );

Class Syntax

Parameters

Class Name Skeleton

Parameter Name Description Type Supported Values Default Value
input
inputBinaryImage
The binary input image. Image Binary nullptr
output
outputBinaryImage
The binary output image. Its size and type are forced to the same values as the input. Image nullptr

Object Examples

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

Skeleton skeletonAlgo;
skeletonAlgo.setInputBinaryImage( polystyrene_sep );
skeletonAlgo.execute();

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

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

skeleton_algo = imagedev.Skeleton()
skeleton_algo.input_binary_image = polystyrene_sep
skeleton_algo.execute()

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

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

Skeleton skeletonAlgo = new Skeleton
{
    inputBinaryImage = polystyrene_sep
};
skeletonAlgo.Execute();

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

Function Examples

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

auto result = skeleton( polystyrene_sep );

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

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

result = imagedev.skeleton( polystyrene_sep )

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

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

IOLink.ImageView result = Processing.Skeleton( polystyrene_sep );

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