In this investigation a wavelet transform was used to decompose
beta-radiographic formation images into spectral and spatial components.
Conventional formation analysis may use spectral analysis, based on
Fourier transformation or variance vs. zone size, to describe the grammage
distribution of features such as flocs, streaks and mean fiber
orientation. However, these methods have limited utility for the analysis
of statistically stationary data sets where variance is not uniform with
position, e.g. paper machine CD profiles (especially those that contain
streaks). A continuous wavelet transform was used to analyze formation
data arrays obtained from radiographic imaging of handsheets and cross
machine paper samples. The response of the analytical method to grammage,
floc size distribution, mean fiber orientation and sensitivity to feature
localization were assessed. From wavelet analysis, the changes in scale of
grammage variation as a function of position was used to demonstrate
regular and isolated differences in the formed structure.