| Image analysis is concerned with the extraction of quantitative information from images captured in digital form (Fortey 1995). Visual information has always played an important role in the Geosciences — indeed, many disciplines rely heavily on the content of images, whether they are sketches drawn in the field, or descriptions of microscopic slides (Jongmans et al. 2001). Visual charts are often used in sedimentology in order to provide some semi-quantification, such as for instance, Krumbein’s grain roundness classes (Krumbein 1941), classification of ichnofabric (Droser and Bottjer 1986), or simply the chart of phase percentages sitting nearby every binocular microscope. However, with the noticeable exception of remote sensing, compared to other disciplines image analysis has been slow to develop in the Geosciences, despite its potential usefulness. One problem with image analysis studies of geologic material is that objects are generally less homogenous than biologic or medical samples, and observation conditions are more variable.
Digital imaging systems were the exception in the 80’s, because the computers needed to process sizeable images were cutting edge and expensive systems, mostly entirely tailored for that unique purpose. The decreasing price of personal computers, with their simultaneous and dramatic increase in performance, made digital image processing more accessible to researchers in the 90’s. Soil scientists, especially micromorphologists, have been very active in the development of newimage analysis tools (e.g.,Terribile and Fitzpatrick (1992), VandenBygaart and Protz (1999), Adderley et al. (2002)). The growing interest for image analysis in Earth Sciences is revealed by the increasing number of initiatives to bring image analysis into the spotlight. Without being exhaustive, one can mention a number of meetings on the subject (e.g., Geological Society of London, London, UK, September 1993, and Geovision held in Liège, Belgium, in May 1999), an increasing number of papers in journals such as Computers & Geosciences, and books (e.g., De Paor (1996)). In the second volume of the Developments in Paleoenvironmental Research (DPER) series, a chapter by Saarinen and Pettersen (2001) was already devoted to image analysis applied to paleolimnology. |