The use of image analysis to quantify soft rot decay
P J Wickens, R J Murphy
Image analysis techniques can provide quantitative information from visual images. As part of a wider interest in decay assessment methods we have investigated the application of image analysis techniques for quantifying soft rot decay by Chaetomium globosum in transverse sections of birch wood and bamboo. A method for reducing contamination of the section (and image) by the fungal hyphae and of staining prior to image analysis was developed. Decay cavities could be accurately detected and the extent of decay expressed in several different forms, with decay as a proportion of the wall area under analysis being the standard notation. Using a thin section exposure system it was found that, after a four day lag phase, soft rot decay in bamboo fibres increased at a constant rate, reaching 60% of wall area after fourteen days. The image analysis technique is rapid and straight forward to use, enabling the collection of both quantitative and qualitative data from the same area. It also allows different regions of a sample to be analysed separately. Further work with the technique is in progress to quantify decay in a wider range of timbers and to assess the effect of preservative treatments.