Module: Split Connected Components ()

Description:

Note: This module is currently available only on Windows.

This module splits the largest connected components from a volume containing several parts.

First, a threshold must be applied interactively to select only values that represent connected components to be split. Next, the number of components, N, to split must be specified. If the value is too small, not all of the desired components will be extracted; if it's too high, unwanted components may be extracted, for example, noise. Finally, pressing the Apply button starts the calculation. The N largest connected components are extracted, and a new data volume for each extracted component is created.

Connected components will be cropped with a border of 8 voxels to the edges of each part.

Parts will be named myVolume.component, myVolume2.component, ... and to be able to predict what will be the number of a component the outputs will be numbered according to the value of the angle represented by the "-Y" axis starting from the center of the input to the center of the each 3D bounding box. The part which will represent the smallest angle will be the one with the smallest number.

Figure 1: The Y axis with its origin at the center of the input volume.

Figure 2: The angle represented by the bottom right part. The red squares represent the bounding box of each part. The "X" red crosses represent the centers of each bounding box. In this case, the angle of the bottom right part is 135°.

By extracting a component, it sometimes possible that the result contains a part of another component. To avoid it, a mask can be applied on results. This mask can be defined by the port "Component Masking". Three options are available:

• none: No Masking. The result can contain part of another component.
• extraneous components: Voxels belonging to another components are replaced by the padding value.
• exterior: Voxels which not belong to the component are replaced by the padding value. Consequently, background is also removed.

Default padding value is computed automatically: in case an Intensity Range Partitioning has been computed, the default padding value will be the mean of the first "exterior" region. In case the data has no Intensity Range Partitioning, the default padding value will be the minimum intensity value. However, this value can be changed with the port "Padding Value". Default padding value is also used to set value of voxels in the border in case this border is outside the data.

Note that only Uniform Scalar Field objects can be connected to this module.

This module is useful when a scanner can scan several objects at the same time, generating a data volume containing multiple parts.

Connections:

Data [required]
Image data where connected components must be split.

Ports:

Number Of Components

Number of connected components to be split from the volume. If the value is too small, not all of the desired components will be extracted; if it's too high, unwanted components may be extracted, for example, noise.

Component Masking

This port will select the component masking to apply:

• none: No Masking. The result can contain part of another component.
• extraneous components: Voxels belonging to another components are replaced by the padding value.
• exterior: Voxels which not belong to the component are replaced by the padding value. Consequently, background is also removed.

Connectivity

This port defines the connectivity type. In the case of Face voxels with a common face are considered connected. In the case of Edge voxels with at least one common edge are considered connected, and, in the case of Corner, voxels with at least one common vertex are considered connected.

Padding Value

This port specifies by which data value voxels are replaced when a masking is selected in the port "Component Masking". It is also used to set value of voxels in the border in case this border is outside the data. Default padding value is computed automatically: in case a Intensity Range Partitioning has been computed, the default padding value will be the mean of the first "exterior" region. In case the data has no Intensity Range Partitioning, the default padding value will be the minimum intensity value.

Orientation

This port provides buttons for setting the slice orientation: xy perpendicular to the z-axis, xz perpendicular to the y-axis, and yz perpendicular to the x-axis.

Colormap

Choose a colormap to map data to colors.

Slice Number

This slider allows you to select different slices. The slices may also be picked with the mouse and dragged directly in the 3D viewer.

Minimum-Threshold

Specifies the lower value of the threshold interval.

Maximum-Threshold

Specifies the upper value of the threshold interval.