Characterisations of fibre networks in paper using micro computed tomography images

Although several methods exist for characterisation of the morphology of wood fibres, the application of these procedures for the analysis of paper microstructure has been limited due to their complexity or shortcomings. Here, a methodology for microstructure characterisation of individual fibres, as well as paper, is presented which is based on three dimensional computed tomography images of paper at micrometer resolution. The first step of the method consists of a graphical user interface (GUI), designed to minimize the amount of manual labour. To manually identify a fibre from a 2 x 2 mm2 paper sheet takes about one minute with this GUI. Then several algorithms are available to analyse the image data automatically guided by the user input. With this approach it is possible to measure several characteristic properties without complete segmentation of the individual fibres. The methodology includes a method to calculate the contact areas between fibres even in extreme cases of severely deformed fibres, which are naturally present in paper. Among the measurable properties are also estimators for the free fibre lengths and fibre wall thickness.