Generating Convex Hulls from Multi-ROIs

Dragonfly lets you generate convex hulls in which each labeled class of the multi-ROI will be a filled or outlined multi-ROI or a mesh. Convex hulls are calculated from the minimum set of points that define a polygon containing all of the labeled voxels of each class in the multi-ROI. If you imagine the points as pegs on a board, you can find the convex hull by surrounding the pegs by a loop of string and then tightening the string until there is no more slack.

In the illustration below, convex hulls were generated from a multi-ROI with three classes of grouped particles.

Original multi-ROI (left) and convex hulls generated filled multi-ROIs (center) and as outlined multi-ROIs (right)

Convex hulls

Convex hull types
Type Description
Multi-ROI, Each Label Being Filled Generates a new multi-ROI in which each labeled class of the multi-ROI is a filled convex hull.
A Multi-ROI, Each Label as an Outer Shell Generates a new multi-ROI in which each labeled class of the multi-ROI is an outlined convex hull.
A Mesh for Each Multi-ROI Label Generates a series of meshes as convex hulls, one for each labeled class of the multi-ROI.
How to Generate a Convex Hull from a Multi-ROI
  1. Right-click the required multi-ROI in the Data Properties and Settings panel.
  2. Choose Generate Convex Hull As in the pop-up menu and then the type of convex hull(s) you want to generate.

    The Binning dialog appears.

  3. Select a Binning factor within the range of 1 to 8, as required.

    Note Binning is the downsampling factor used when generating the space where the convex hull is created prior to its re-projection in the initial space.

  4. Click OK to generate the convex hull(s).