Optimal laser marking of 2D data matrix codes on Cavendish bananas

Abstract

A traceability system is an effective tool to guarantee safety in horticultural products and to improve supply chain transparency. A direct data matrix (DM) code created with carbon dioxide laser (wavelength 10.6 μm) can be used as a trust mark on bananas. In this study, green bananas were marked with the above-mentioned CO2 laser. Subsequently, the samples were held under storage conditions. Images of the codes on bananas were captured by using two different cameras; i.e. hyperspectral imaging camera and charge-couple device (CCD) camera. Image processing was used for evaluating print quality of 2D codes based on the ISO/IEC 15415 standard. The quality of the codes on bananas mainly depends on some parameters: laser power, laser energy, marking time per module and storage time. The best readability results were achieved by using laser power of 1.8 W and marking time of 0.09 s per data matrix module, whereby an 80-100% readability of DM codes after the storage was obtained.