Module: Crop ()

Description:

This module works on 3D fields with an arbitrary number of components defined on a regular grid, e.g., 3D images or 3D vector fields with uniform, stacked, rectilinear, or curvilinear coordinates. It allows you crop such a field, i.e., to discard all voxels lying outside of a specified subvolume in index space.

Each node of a regular grid can be addressed by an index triple (i,j,k). Each index ranges from zero to the number of slices minus one in that direction. This module allows you to add new slices on every side in every dimension.

Connections:

Data [required]
The data to crop.

Ports:

Min index

The minimal integer values of the crop coordinates. These values can be smaller than the initial values (even negative) to add new slices.

Max index

The maximal integer values of the crop coordinates. These values can be greater than the initial values to add new slices.

Threshold

The Auto crop button automatically adjusts the subvolume to be cropped by taking into account the value of the Threshold field. Slices at the boundaries of the original data volume are cropped if they contain only data values smaller than the specified threshold. In this way it is easy to isolate a bright object in a 3D image with a large dark background.

Adjust

This port allows you to automatically enlarge or reduce the crop region by taking into account the value of the Adjust field. Each click on the Enlarge or Reduce buttons will enlarge or reduce the crop region with n number of voxels. By default, the default value is set to 8 voxels.

Add mode

In order to add slices, you must set the indices in the text fields beyond the limits of the total data volume. When slices are added, by default the values of the last slice in that direction are replicated. If you switch off the replicate toggle, the text field pixel value becomes active. You can then specify a data value which is used to initialize the new slices.