Determining the average annual ring width on the front side of lumber

Pith Estimation on Rough Log End Images using Local Fourier Spectrum Analysis

“…[5] and [6]) and additionally three methods for local orientation estimation using Fourier Spectrum analysis are described. First, two approaches for Fourier Spectrum preprocessing of annual ring sections are described.…”

“…The more uniform the local annual ring pattern is, the more the Fourier Spectrum converges to a single point. PA for pith estimation was introduced by [5] with the intention to count existing annual rings on rough log end boards from the two top end board edges into the direction of the pith. For this purpose, the presence of the pith on the board is not required.…”

“…With intersection of the local orientations the pith position is determined. The experiments of [5] indicate that pith estimation using local Fourier Spectrum analysis could also be applied on images from rough log ends. So far the only work focusing on the treatment of images of rough log ends was presented by [7] utilizing two local Fourier Spectrum analysis methods suggested in [8] and [9].…”

“…Local orientation estimation approaches for pith estimation are shown in [5], [6] and [7]. The former two use local Fourier Spectrum analysis for pith estimation on rough log end boards and on well prepared cross section discs, respectively.…”

“…For this purpose the Peak Analysis Method ( [5] and [6]) and further three Fourier Spectrum Analysis methods are used to compute local orientations of small sections from cross section images, denoted as annual ring sections. Contrary to [7] it is shown that local orientation estimation in the Fourier domain is applicable for annual ring sections from rough log ends.…”