Volume Fusion was added to Vision4D as a tool to merge multiple image volumes that could not be merged otherwise. There are several reasons why two image volumes could not be merged:

• They may not have the same orientation - Stitching using the Tile Sorter only works if the volumes have the same Z-axis direction
• They may not have the same dimensions or resolution - this is also a pre-requisite for the Tile Sorter

Volume Fusion has been designed to work around these limitations.

This enables a few specific applications which would otherwise not be practically possible, including for example:

• Merging images of a sample that cannot be imaged in a single acquisition because it extends beyond the range of the field of view or stage movement. In this case, we might capture as much of the sample as possible, maybe including tiling, repositioning the sample, and imaging another part of it.
• Merging images of two parts of the same volume. This is an extension of the task above. If the sample is too large to fit in the imaging chamber, it may be possible to separate the sample into its constituent parts, image each of these individually, then merge them using Volume Fusion.
• Merging images taken in different modalities. Multiple modalities are available for imaging samples, from light microscopy, whether widefield or fluorescence, to electron microscopy and topical spectral imaging (e.g. IR microscopes). Such acquisitions have different outputs and sample preparation steps and will often result in images of different sizes, calibrations, and channel colors.

In all of these cases, and more, Volume Fusion can be used to generate a single volume from two separate volumes, and that fused volume can be used for analysis and visualisation like any other dataset.