# Geometric Characterization of Vines from 3D Point Clouds Obtained with Laser Scanner Systems
## 3 Results  
### 3D Point Cloud Acquisition and Preprocessing  
The input data acquisition performed in the test area with the TLS equipment resulted in a colored and georeferenced point cloud. It was performed via six scan stations (Figure 5) with five calibrated spheres as targets for scan joining and georeferencing. The mean target distance error was 9.98 mm and 0.021\({}^{\circ}\), with a deviation of 1.57 mm and 0.009\({}^{\circ}\). The configuration parameters were as follows: a horizontal resolution of 10,240 points, a vertical resolution of 4267 points, a horizontal angular area of 0\({}^{\circ}\) to 360\({}^{\circ}\), a vertical angular area of 90\({}^{\circ}\) to -60\({}^{\circ}\), and 4\(\times\) quality.  
The GPS positions registered by this equipment have a precision with a 5 m error. Each scan station takes 11.15 minutes.  
The same area covered by the MMS collected a colored and georeferenced point cloud. The start and stop angles of its scanners were 65\({}^{\circ}\) to 185\({}^{\circ}\), 65\({}^{\circ}\) to 185\({}^{\circ}\), -5\({}^{\circ}\) to 185\({}^{\circ}\), -5\({}^{\circ}\) to 115\({}^{\circ}\), and -5\({}^{\circ}\) to 115\({}^{\circ}\). These angles are suitable according to the assembly and position of the scanners in the platform and the occlusions that define the rest of the equipment of the system, including the vehicle itself. The assembly of the scanners can be seen in Figure 4b. The scan frequency was set to 100 Hz, and the pulse repetition frequency (PRF) for the system configuration was 134,000 points per second. The contamination level was set to level 2 for all of them. Level 2, for this equipment, is a high level of contamination that fits the requirement of the agricultural environment in which the data were acquired. The spherical camera captured images in 5 m intervals. The recording of the GPS observations was kept at 10 Hz. The capture lasted 27 minutes and drove 1.7 km due to the maneuvers and the obstacles that the driver of the vehicle had to avoid. The car's advance speed was set to approximately 1 m/s to increase the cloud point density.  
Both clouds were cut with the same defined area of 18.15 m\({}^{2}\), which included six vines (represented in Figure 5). The TLS cloud had 5,613,180 points, while the one captured with the MMS had 188,984 points.  
For data acquisition from the real vineyard, the same capture configuration was used as in the test area. The scanning work was divided into four independent captures of 34, 50, 54, and 35 minutes, covering a total of 27.2 km. It should be noted that despite the size of the scanned area, the vehicle had to find accesses to the strips and have a clear path for kinematic alignment at the beginning of each shot. Thus, the distance travelled far exceeds the actual scanning distance. The environmental acquisition conditions (reflection, dust, etc.) and the characteristics of the equipment's techniques generated several outliers, which were cleaned with a filter using points based on an intensity value between 225 and 826 and a minimum threshold of four neighbors in a cube with a 0.09 m sized side.  
The final point cloud clipped to the experimental zone (0.58 ha; represented in Figure 3) produced 38,833,904 points.  
Point cloud preprocessing was done with the parameters reviewed in Table 8. These parameters were determined by the conditions of the capture. Each situation (sensor, meteorology, crop status, etc.) has specific characteristics to which these parameters have been adapted. The election of dimensional parameters was established considering such aspects as the point density of the clouds, the plantation framework, and the vine size or its prune. For outlier removal, we considered ambient conditions(i.e., dust presence); the skill of the equipment operator and vehicle driver, as well as ground conditions (for constant-speed scanning); and the equipment's functional requirements and limitations.  
Manual editing of the point cloud was done in the segmented vines when the results were anomalous.