ImageDev

OpeningDisk3d

Performs a three-dimensional opening using a structuring element matching with an oriented disk.

Access to parameter description

For an introduction: This algorithm successively runs an ErosionDisk3d and a DilationDisk3d with the same kernel.
The opening disk normal is oriented in the direction given by ($\theta$, $\varphi$) in spherical coordinates as often used in mathematics (azimuthal angle, $\theta$ and polar angle, $\varphi$). This direction is described with the following formula: $$V=\left[\begin{array}{c}; v_x\\ v_y\\ v_z\end{array}\right] = \left[\begin{array}{c}; \sin(\varphi)\cos(\theta)\\ \sin(\varphi)\sin(\theta)\\ \cos(\varphi)\end{array}\right]$$ This direction can be illustrated on the unit sphere:

<b> Figure 1.</b> Azimuthal and polar angles on the unit sphere
Figure 1. Azimuthal and polar angles on the unit sphere


With a classic implementation, morphological opening systematically considers areas out of the image as a replication of the image borders at each step of the algorithm. Therefore, when applying an opening, some thin object parts cut by the image borders may be removed at the erosion step and not be restored after the dilation, while one would expect to keep them. The borderPolicy parameter manages this case. The default mode, LIMITED, corresponds to the classic behavior. The EXTENDED mode manages properly image borders by extending them by a size equal to the structuring element's. This mode can be slower and more memory consuming, especially when the structuring element size is high.
This option is illustrated in the Opening2d documentation (Figure 2).

See also

Function Syntax

This function returns the outputImage output parameter. 
// Function prototype.
std::shared_ptr< iolink::ImageView >
openingDisk3d( std::shared_ptr< iolink::ImageView > inputImage,
               double thetaAngle,
               double phiAngle,
               uint32_t kernelRadius,
               OpeningDisk3d::BorderPolicy borderPolicy,
               std::shared_ptr< iolink::ImageView > outputImage = NULL );
This function returns the outputImage output parameter. 
// Function prototype.
opening_disk_3d( input_image,
                 theta_angle = 0,
                 phi_angle = 0,
                 kernel_radius = 3,
                 border_policy = OpeningDisk3d.BorderPolicy.LIMITED,
                 output_image = None )
This function returns the outputImage output parameter. 
// Function prototype.
public static IOLink.ImageView
OpeningDisk3d( IOLink.ImageView inputImage,
               double thetaAngle = 0,
               double phiAngle = 0,
               UInt32 kernelRadius = 3,
               OpeningDisk3d.BorderPolicy borderPolicy = ImageDev.OpeningDisk3d.BorderPolicy.LIMITED,
               IOLink.ImageView outputImage = null );

Class Syntax

Parameters

Class Name OpeningDisk3d

Parameter Name Description Type Supported Values Default Value
input
inputImage
The input image. The image type can be integer or float. Image Binary, Label, Grayscale or Multispectral nullptr
input
borderPolicy
The border policy to apply.
LIMITED The limited mode is faster to compute, but can produce the unexpected results for particles close to the image border.
EXTENDED The Extended mode is slower to compute, but produces the expected results for particles close to the image border.
Enumeration LIMITED
input
thetaAngle
The azimuthal angle in degrees. Float64 Any value 0
input
phiAngle
The polar angle in degrees. Float64 Any value 0
input
kernelRadius
The length of the disk radius in voxels. UInt32 >=1 3
output
outputImage
The output image. Its dimensions and type are forced to the same values as the input image. Image nullptr

Object Examples

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

OpeningDisk3d openingDisk3dAlgo;
openingDisk3dAlgo.setInputImage( foam );
openingDisk3dAlgo.setThetaAngle( 0 );
openingDisk3dAlgo.setPhiAngle( 0 );
openingDisk3dAlgo.setKernelRadius( 3 );
openingDisk3dAlgo.setBorderPolicy( OpeningDisk3d::BorderPolicy::EXTENDED );
openingDisk3dAlgo.execute();

std::cout << "outputImage:" << openingDisk3dAlgo.outputImage()->toString();

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

opening_disk_3d_algo = imagedev.OpeningDisk3d()
opening_disk_3d_algo.input_image = foam
opening_disk_3d_algo.theta_angle = 0
opening_disk_3d_algo.phi_angle = 0
opening_disk_3d_algo.kernel_radius = 3
opening_disk_3d_algo.border_policy = imagedev.OpeningDisk3d.EXTENDED
opening_disk_3d_algo.execute()

print( "output_image:", str( opening_disk_3d_algo.output_image ) );

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

OpeningDisk3d openingDisk3dAlgo = new OpeningDisk3d
{
    inputImage = foam,
    thetaAngle = 0,
    phiAngle = 0,
    kernelRadius = 3,
    borderPolicy = OpeningDisk3d.BorderPolicy.EXTENDED
};
openingDisk3dAlgo.Execute();

Console.WriteLine( "outputImage:" + openingDisk3dAlgo.outputImage.ToString() );

Function Examples

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

auto result = openingDisk3d( foam, 0, 0, 3, OpeningDisk3d::BorderPolicy::EXTENDED );

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

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

result = imagedev.opening_disk_3d( foam, 0, 0, 3, imagedev.OpeningDisk3d.EXTENDED )

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

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

IOLink.ImageView result = Processing.OpeningDisk3d( foam, 0, 0, 3, OpeningDisk3d.BorderPolicy.EXTENDED );

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