|Type||Master thesis presentation|
|Title||Measurement of Local Filler Content in Paper|
|Abstract||A Master of Science Thesis on Induced Fluorescence Photography and Digital Image Analysis.
Variations in paper structure are of major importance to the manufacturing process. Together with filler they affect the optical and mechanical properties of the finished paper product. The aim of this thesis is first to try to evaluate and second to further develop the usability of, a new method for measuring the distribution of filler content in paper. Digital image analysis, based on images from induced fluorescence photography on paper sheets, split by a lamination technique developed at STFI-Packforsk, is to be used to accomplish this.
A review of the literature on the topic is done, focus is put on the spatial distribution of filler. Later a method for splitting of paper samples is introduced, followed by a description of the appropriate ways of acquiring images. The proper set-up for the image acquisition process is determined, and a suggestion of suitable digital image analysis tools are designed and evaluated. After attempting to acquire suitable photographs, image segmentation is tried in order to extract images of filler material clusters. A combination of image filters and morphology transforms is evaluated as a method to extract this information. A 3D visualisation of the filler distribution follows. Finally a check for validity of the photographies is done using a optical sample mass measurement and a statistical approach. During this project, MATLAB-code is developed to perform these image analysis operations.
Accurate photographies describing the filler distribution could not be obtained. Therefore this method could not be tested thoroughly. The recommendation is nevertheless not to develop this method further due to the unreliability discovered. Interesting — and possibly usable — discoveries might have been made in the process of coming to this conclusion. If so, the effects of these remain to be seen.