# Pore descriptors#

## Scalars describing the pore geometry#

For describing the pore geometry, we heavily rely on methods implemented in the zeopp package.

The most commonly used pore-geometry descriptors (surface areas, probe accessible pore volumes, …) are computed with a probe approach. By means of “simple” geometry analysis one can also extract pore radii.

We use the implementation in the zeopp package [Willems2011]. |

We use the implementation in the zeopp package [Willems2011]. |

We use the implementation in the zeopp package [Willems2011] [Ongari2017]. |

## Histograms#

An alternative to scalar descriptors are “summaries” of the pore geometry in histograms. One approach for instance is to shoot random rays (orange in the figure below) through the structure and use the length of the ray between the points where it intersects the pores as ray length. If one performs this experiment often, one can summarize the observed ray lengths in a histogram.

Another, quite sparse, alternative is to use the pore size distribution (PSD) of the structure. That is, PSD histograms measure what fraction of the void space volume corresponds to certain pore sizes. One might also use this as cumulative distribution or take the derivative.

We use the implementation in the zeopp package. The feature itself was described and used in [Pinheiro2013]. |

We use the implementation in the zeopp package. The feature itself was described and used in [Pinheiro2013]. |