Comparison Between TLS and viDoc RTK for High Resolution Geometric Characterization of Hazelnut Plants

The geometric characterization of fruit trees plays a key role in modern orchard management, supporting agronomic practices such as vigor assessment, irrigation optimization, and canopy management. This study presents a comparative analysis of two surveying techniques applied to the geometric characterization of hazelnuts (Corylus avellana L.) plants, with the aim of evaluating their effectiveness in capturing plant-related morphological information for applications in orchard monitoring and precision agriculture. The first method employs Terrestrial Laser Scanning (TLS), which provides high-density and high accuracy point clouds. The second method uses an iPhone combined with the viDoc RTK (Real Time Kinematic) Rover, a mobile photogrammetric solution capable of generating georeferenced point clouds in real time through RTK GNSS integration. The two point clouds, derived respectively from TLS and iPhone with viDoc acquisitions, were processed and compared to extract and evaluate key morphological parameters, including tree height, canopy area, and canopy volume. Quantitative comparisons were carried out both at the point cloud level and on the extracted geometric descriptors. The results show a good overall agreement: height differences were within a few centimeters, while canopy area and volume discrepancies were less than 10%. Variations are attributable to differences in point density, occlusions, and the level of structural detail captured by each method. These findings highlight the potential of smartphone-based RTK photogrammetry as a lightweight, portable, and flexible solution for vegetation surveys, offering practical advantages in terms of mobility and ease of use in field conditions.