**3. Results**

*3.1. Evaluation of Canopy Extraction Quality*

3.1.1. Canopy Area Consistency

A difference in canopy area was evident between the two RGB-BM images on 21 July and 12 August (Figure 3): the median values were 414 and 474 m2, respectively. This is a difference of 60 m2, while slight differences were observed between these dates with the 2PE, ED, and VS methods: 6, 4, and 3 m2, respectively. Accordingly, a significant difference in canopy area mean (increase) was calculated between the two RGB-BM images (*p* < 0.001, n = 22 MC per date), while no difference was detected for the 2PE, ED, or VS methods (*p* > 0.05, n = 22 MC per date).

**Figure 3.** Canopy area (m2) per management cell (MC) (black dots) and box plot (red) per day of image acquisition (21 July–26 August 2019). The black horizontal line is the grand mean. The green boxes indicate data from 21 July and 12 August of the 2-pixel erosion (2PE), edge detection (ED), and vegetation segmentation (VS) methods. The RGM binary masking (RGB-BM) method was performed only on these dates. Note: the Y-axis range of the VS method is specifically different from the other methods.

The canopy area consistency of the 2PE, ED, and VS methods was evaluated using ten thermal images (Figure 3). The 2PE and VS methods were more consistent compared to the ED method. The median values per date of the 2PE ranged from 374 to 430 m<sup>2</sup> (a difference of 56 m2), and the values ranged from 555 m2 to 626 m<sup>2</sup> (a difference of 71 m2) with the VS method. In contrast, the median values of the ED method ranged from 288 to 460 m2 (a difference of 172 m2, 3-fold of the 2PE method), indicating less consistency over time. The coefficient of variation (CV) values of the 2PE, VS, and ED methods were 0.05, 0.04, and 0.13, respectively, highlighting the differences in consistency.

#### 3.1.2. Accuracy Assessment

The differences in canopy area identification accuracy were evident between the canopy extraction methods (Figure 4). The RGB-BM method was found to be the most accurate among the canopy extraction methods, as demonstrated through the overall accuracy and the F1-score values on both 21 July and 12 August. On 21 July, the recall values of all of the methods were high (90–97%), indicating that most of the actual canopy was correctly classified. The precision, or the degree to which the classified map correctly identified canopy, however, varied according to extraction method: the 2PE and RGB-BM methods' precision was fairly high (84%), while the VS method's precision was the lowest (62%). On 12 August, the recall values of the VS and RGB-BM methods were higher than the 2PE and ED methods. The precision of the 2PE method was slightly less than the RGB-BM method (78%), and the ED method's precision was the lowest (68%).

**Figure 4.** Overall accuracy (blue bars) of canopy/non-canopy classification and precision (red bars), recall (yellow bars), and F1-score (grey bars) parameters of canopy classification as measured with a confusion matrix per date for the 2-pixel erosion (2PE), edge detection (ED), vegetation segmentation (VS), and RGB binary masking (RGB-BM) canopy extraction methods.
