Image analysis for core geological descriptions: strata and granulometry detection

Digital signal processing is commonly used in Geophysics. Methods combining core sample physical property measurements with image analysis are beginning to emerge. In this paper, we describe a digital processing method applied directly to core sample images. Our approach uses a number of time-frequency and scale-frequency transformations as well as morphological operators that reach a resolution equivalent to and even better than the geologist´s eye. The resources presented below are free from operator-related subjectivity and provide efficient, reliable and repeatable sequential descriptions of geological borehole samples that include both layer detection and grain analysis. Our process´s efficiency is demonstrated through analyses carried out on a number of core samples taken from Cretaceous to Upper Eocene volcano-sedimentary series on New Caledonia´s West Coast.