An automated method for tree-ring delineation based on active contours guided by DT-CWT complex coefficients in photographic images: Application to Abies alba wood slice images

• Our method can be used to delineate successive concentric tree-rings in Abies alba images.
• We coupled the Q-Shift DT-CWT and the points-based active contour model.
• Notions such as attraction power and orientation simulate an external force field.
• Our method performed as well as experts delineations on 200 tree-rings.

This paper describes an efficient method for delineating tree-rings and inter tree-rings in wood slice images. The method is based on an active contour approach and a multi-scale gradient map resulting from the Dual Tree Complex Wavelet Transform (DT-CWT). The method is automated and does not require any pith localization. It is also quite robust to some defect structures such as branch prints, cracks, knots or mold. We applied the method to process entire Abies alba wood slices (aged from 10 to 50 years) from bark to pith, which amounted to about 200 tree-rings. Our automatic delineation method performed accurately compared to the manual expert measurements with a mean F-score of 0.91 for the quality of delineation.