# Intelligent Control System to Irrigate Orchids Based on Visual Recognition and 3D Positioning
## 3 Results and Discussion
### Experiments of Automatic Irrigation System  
Two respective experiments for the single and multiple seedlings were considered in the experimental configuration of the automatic irrigation system. In the configuration for the single-seeding experiments, as shown in Figure 28, the triggering area in the identification screen was split into five sections, named as Upper left, Lower left, Central, Upper right, and Lower right, as denoted in Figure 29.  
In order to numerically evaluate the experimental results, three types of indexes are defined. The first type is the number of correct watering to the stem-root junction, as depicted in Figure 30. The second type censuses the achievements of watering to the junction between stems and leaves, as highlighted in Figure 31. The third type stands for counting the incidents of improper watering to the leaf and colliding of nozzle with the leaf, as described in Figure 32. Two kinds of the watering effectiveness are formulated by Equations (4) and (5). \[\text{Success watering rate }(\%)=\frac{(\text{\# 1 st type}+\text{\# 2 nd type})}{(\text{\# 1 st type}+\text{\# 2 nd type}+\text{\# 3 rd type})} \tag{4}\]  
\[\text{Perfect watering rate }(\%)=\frac{\text{\# 1 st type}}{(\text{\# 1 st type}+\text{\# 2 nd type})} \tag{5}\]  
where # 1 st type, # 2 nd type, and # 3 rd type are the resultant counts of watering with the first, second, and third types, respectively. Figure 28: The configuration for the single-seeding experiments. Figure 29: Five sections in the triggering area of the camera. In this experiment, the distance from the optical center of the left lens of the camera to the ground is 64.1 cm. The potted plants were placed in five sections, as shown in Figure 29, and watering will be repeated with ten times. Finally, Table 2 addresses that the total successful and perfect watering rates are 82% and 70.7%, respectively. Whether the watering position is proper could be impacted by the obtainment of an incorrect leaf vector, due to surplus dilation and erosion on the framed orchid image. However, among the records in Table 2, it can be found that there is a low occurrence ratio for the improper watering, which shows that the system can be feasibly applied to practical customized watering onto orchids. Figure 31: Demonstration of watering on the junction between the stem and leaves. Figure 30: Demonstration of watering on stem-root junction. Figure 30.0 Demonstration of watering on the wrong position (collision of sprinkler with leaves). For the multiple-seedling experiments, four pots of seedlings were placed in a rectangular manner in the pot holder, as displayed in Figure 33, where the seedlings were spaced by 9 cm and 18 cm, respectively, for the vertical and horizontal directions. Figure 34 demonstrates the experimental configuration for placing the four pots of seedlings in the triggering area. In addition to the three types of indexes to leverage the watering results of the single-pot experiments, the fourth-type index is also provided to accumulate the failures of watering due to the surplus Z-axis distance error, given by Equation (6). Figure 30.1  
During the multiple-seedling experiments, the distance between the ground and the optical center of the left lens of the camera is 64.1 cm. The experiment was repeated by 15 times to collect 60 resultant sets. Finally, the statistic results of watering provide that the rates of operated, successful, and perfect watering are 70%, 83.3%, and 62.9%, respectively. The experimental statistics are demonstrated in Figure 30.2