A 3D contour based geometrical model generator for complex-shaped horticultural products

A novel geometric model generator for horticultural products is presented, which generates 3D models of fruits using shape description techniques based on shapes obtained experimentally from a measured dataset of fruits by non-destructive X-ray CT imaging. For this purpose, the 3D contour of each fruit in the scanned dataset was represented with a 2D shape signature, obtained after applying the spherical coordinate transformation. After normalisation, these signatures were described with 2D Fourier descriptors. Statistical analysis of these descriptors for all scanned fruits allowed automatic generation of new geometric fruit models, representative of the measured dataset. The accuracy of the generator was validated by means of the distributions of volumes and surface area to volume ratios of fruit scans and the newly generated shapes. This 3D shape description and generation method allows to process the entire 3D contour of the observed objects and can be applied to all star-shaped objects (shapes that do not curve back on themselves with respect to the centre of mass). This way, more accurate geometrical models can be produced compared to similar model generators based on shape description using 2D cross-sections. This generator enables fast generation of geometrical models to be used in numerical simulations of heat or mass transport phenomena within horticultural products or their exchange processes with the surrounding environment. (C) 2015 Elsevier Ltd. All rights reserved.