Module: ReassignObjectNumbers

Reassign Object Numbers renumbers previously identified objects.
Objects and their measurements are associated with each other based on their object numbers (also known as labels). Typically, each object is assigned a single unique number, such that the exported measurements are ordered by this numbering. This module allows the reassignment of object numbers by either unifying separate objects to share the same label, or splitting portions of separate objects that previously had the same label.

Available measurements

Parent object measurements:

Reassigned object measurements:

Technical notes

Reassignment means that the numerical value of every pixel within an object (in the label matrix version of the image) gets changed, as specified by the module settings. In order to ensure that objects are labeled consecutively without gaps in the numbering (which other modules may depend on), ReassignObjectNumbers will typically result in most of the objects having their numbers reordered. This reassignment information is stored as a per-object measurement with both the original input and reasigned output objects, in case you need to track the reassignment.

See also RelateObjects.


Select the input objects

Select the objects whose object numbers you want to reassign. You can use any objects that were created in previous modules, such as IdentifyPrimaryObjects or IdentifySecondaryObjects.

Name the new objects

Enter a name for the objects whose numbers have been reassigned. You can use this name in subsequent modules that take objects as inputs.


You can choose one of the following options:

Maximum distance within which to unify objects

(Used only with the Unify option and the Distance method)
Objects that are less than or equal to the distance you enter here, in pixels, will be unified. If you choose zero (the default), only objects that are touching will be unified. Note that Unify will not actually connect or bridge the two objects by adding any new pixels; it simply assigns the same object number to the portions of the object. The new, unified object may therefore consist of two or more unconnected components.

Unify using a grayscale image?

(Used only with the Unify option)
Select Yes to use the objects' intensity features to determine whether two objects should be unified. If you choose to use a grayscale image, Unify will unify two objects only if they are within the distance you have specified and certain criteria about the objects within the grayscale image are met.

Select the grayscale image to guide unification

(Used only if a grayscale image is to be used as a guide for unification)
Select the name of an image loaded or created by a previous module.

Minimum intensity fraction

(Used only if a grayscale image is to be used as a guide for unification)
Select the minimum acceptable intensity fraction. This will be used as described for the method you choose in the next setting.

Method to find object intensity

(Used only if a grayscale image is to be used as a guide for unification)
You can use one of two methods to determine whether two objects should unified, assuming they meet the distance criteria (as specified above):

Retain outlines of the relabeled objects?

Select Yes to retain the outlines of the new objects for later use in the pipeline. For example, a common use is for quality control purposes by overlaying them on your image of choice using the OverlayOutlines module and then saving the overlay image with the SaveImages module.

Name the outlines

(Used only if the outline image is to be retained for later use in the pipeline)
Enter a name for the outlines of the identified objects. The outlined image can be selected in downstream modules by selecting them from any drop-down image list.

Unification method

(Used only with the Unify option)
You can unify objects in one of two ways:

Select the parent object

Select the parent object that will be used to unify the child objects. Please note the following: