Application of Image Processing Technique for Analysis on Sheet Structure of Paper II

Evaluation of The Formation of Paper

Abstract

The mass co-occurrence matrix (MCM) technique was applied in order to describe the characteristics of formation of paper. The matrix, which represents the joint probability density distribution of mass density (i. e. local basis weight) of two neighboring points in the sheet, was computed from the digital image of 2-dimensional mass distribution. In this paper, the following types of parameters, which are extracted from MCM and describe the characteristics of formation, were investigated using handsheets (settling time before drainage: 10-100 sec.) and commercial papers.
(1) Textural parameters, which express characteristics of the joint probablity density distribution, were extracted from MCM. Parameters f_a, f_c and fecould express the coarseness and contrast of texture, the intensity of large flocs and the intensity of small flocs, respectively.
(2) Mean floc size was estimated from MCM. The value of mean floc size in handsheets increased with settling time.
(3) A new parameter for the direct comparison of the MCM from each of two sheets was derived using the corresponding elements in the two matrices. The parameter is thought to be more useful than the above parameters for expressing the differences in mass distribution between two sheets.