Octopus Analysis is a 3D analysis program with a user-friendly and intuitive GUI featuring the following functionalities:
Determination of porosity and volume fraction
The total porosity or volume fraction of a certain component can be derived. Additionally, this parameter can be determined for sub-volumes and provide information about local variations. This can be done easily after an initial single or dual (or hysteresis) thresholding and subsequent cleaning operations to simplify the binary volume (opening, closing, hit-or-miss opening and closing, filling holes).
Volume of Interest determination
Octopus Analysis allows for a flexible and intuitive method to determine and select a Volume of Interest (VOI) based on the shape of the entire object, resulting in reliable measurements for the complete sample.
To identify each object (a pore network, air bubble, grain...) inside a volume as being a separate unit connected-component labeling is used. The combination of the threshold operation and the object identification is often called segmentation.
Each object can be characterized by deriving parameters such as the number of voxels, the diameter of maximum inscribed sphere, the diameter of minimum circumscribed sphere, the surface, the orientation, the average gray value, the number of neighboring objects…
Some objects have to be separated into a set of sub-objects. Their individual parameters combined with the information about their interconnectivity (such as the size of the bottlenecks) can be used to improve characterization of the object. Sometimes, this separation is also necessary for disconnected objects which appear connected due to the limited resolution/contrast of a CT scan. To avoid erroneous separation some filtering operations are included in the program. The separation is done by computing the watershed transform of the inverse distance transform. An intelligent rejoining algorithm is featured to undo erroneous separations.