Table 5.
Comparison of LiDAR data in weed, crop and soil detection and crop growth estimation.
LiDAR Type | Analytical Method | Model | Features | Results |
---|---|---|---|---|
Terrestrial | SLR; binary logistic regression; CDA |
Plant height; reflection value |
R2 between LiDAR measured height and actual plant heights was 0.75. The predicted values from binary logistic regression shows an accuracy of 95.3% for vegetation and 82.2% for non-vegetation/soil, with an overall accuracy of 92.7%. Using canonical discriminant analysis (CDA), the overall success to discriminate was 72.2%. The soil and dicots were classified with 92.4% and 64.5% accuracy, respectively [40]. |
|
Terrestrial | CropPointNet; PointNet; DGCNN |
Crop height | CropPointNet model had an overall accuracy of 81.5%. PointNet and DGCNN had overall accuracies of 55% and 66.5%, respectively. CropPointNet, DGCNN and PointNet models discriminated cabbage with 91%, 82% and 72% accuracy, respectively, eggplant with 88%, 83% and 69% accuracy, respectively, and tomato crop with 65%, 61% and 60% accuracy, respectively [41]. |
|
Terrestrial | SLR | Canopy height |
R2 between LiDAR measured height and manual measurement, between UAS measured height and manual measurement and between ultrasonic-sensor-measured height and manual measurement were 0.97, 0.91 and 0.05, respectively [42]. | |
Airborne | Power regression; SLR |
DTM | Sugarcane height |
The ratio of ground to non-ground returns with LiDAR had R2 = 0.971. The ratio of ground to non-ground returns with photogrammetry had R2 = 0.993. R2 between maximum crop height obtained from LiDAR and those obtained from photogrammetry was 0.885. R2 between the mean crop height obtained from LiDAR and those obtained from photogrammetry was 0.929 [43]. |
Airborne | MLR; SMR; GLM; GBM; KRLS; RFR |
DEM; DSM |
AFW | R2 between observed AFW and fitted AFW via RFR was 0.96, the highest value for R2 among the six models [44]. |