Module: Label Analysis ()

Description:

For an introduction, see section Analysis.

The Label Analysis command computes a group of measures on each cell or connected component of the input image, and generates a spreadsheet with the result values. If the input image provides a coordinate unit, result values are expressed according to that coordinate unit. More details about each label measure can be found in the list of available measures.

Note that the analysis results are read-only spreadsheets. Yet, as with any spreadsheet, you can display it in the Tables panel, compute its histogram, plot it, query it from Tcl scripts, and import it into an external spreadsheet program like Microsoft Excel. In order to edit cell values, add or remove rows or columns, you can use the converter Analysis To Spreadsheet.

Connections:

Data [required]
The input label image to be analyzed. If the input is a binary image, it is first turned into a label image by providing a unique identifier to each connected component. The generated label image is then analyzed, and provided as a result of this module.

Intensity Image [optional]
Providing an intensity image, some measures about the gray level statistics of each label may be computed, such as histogram or texture features. For instance, the 'volume' measurement would sum the gray levels of the intensity image for each label. If not set, the input label image is used as the intensity image. In this case, the 'volume' measurement would amount to multiply the index of each label by its number of voxels.

Ports:

Interpretation

This port specifies whether the input will be interpreted as a 3D volume or a stack of 2D images for processing.

• "3D": the module configuration is set to 3D. The image will be processed as a whole in 3D. Some measures are only available in this mode.
• "XY planes": the module configuration is set to 2D. The image will be processed slice per slice. Format of the result then depends on the port Sequence Mode.

Note: 2D measures will not be displayed in the analysis spreadsheet of a 3D volume and vice versa.

Sequence Mode [with "XY planes" only]

If the port Interpretation is set to "XY planes" mode, input images will be processed as an image sequence. Then, two modes of sequence analysis are available with port Sequence Mode :

• Append : This first mode appends the measures results for each plane after the results of previous planes.
• Evol : This second mode takes care of the evolution of each object from the first plane to the last plane. Each object measurement results in a distribution along the planes. WARNING : Each object must own the same label number on each plane where it is present. This check cannot be done by the analysis process and should be verified by the user. In some case, a label object can be missing in some planes, which may affect its global statistics.

Measures

This port defines the group of measures to be computed during analysis. default groups are defined.
The default group for 3D images is basic, and contains the measures Volume3d, Area3d, BaryCenterX/Y/Z and Mean.
The default group for 2D images is basic2D, and contains the measures Area, BaryCenterX/Y and Mean.
The Standard Shape Analysis group computes standard shape parameters of the regions of the input label image.
The Weighted Shape Analysis group computes standard shape parameters of the regions taking into account the grey intensity input data.

Note: The measures are computed in the working unit.

Click on the [...] tool button to open the From this dialog, you will be able to :

• Edit your selection of measures,
• Create custom measures from the existing ones,
• Redefine attributes values of configurable measures.