The term “data fusion” can be defined as “the process of combining data from multiple sources to produce more accurate, consistent, and concise information than that provided by any individual data source”. Other stricter definitions do exist to better fit narrower contexts. This type of approach has been applied to agricultural problems since the first half of the 1990s [6], and there has been an increase in the use of this approach. Arguably, the main challenge involved in the use of data fusion techniques involves finding the best approach to fully explore the synergy and complementarities that potentially exist between different types of data and data sources.
Fused Data | Mean Accuracy | ||||||||
---|---|---|---|---|---|---|---|---|---|
[99] | Root zone soil moisture estimation | NN (M), DRF (M), GBM (M), GLM (M) | 2,11 | 0.90–0.95 | |||||
[100] | Gramineae weed detection in rice fields | Haar wavelet transformation (L) | 1, 2 | 0.70–0.85 | |||||
[65] | Monitoring agricultural terraces | Coregistering and information extraction (L) | 5 | N/A | |||||
[66] | Spectral–temporal response surfaces | Bayesian data imputation (L) | 2, 3 | 0.77–0.83 | |||||
[101] | Phenotyping of soybean | PLSR (L), SVR (L), ELR (L) | 1, 2, 4 | 0.83–0.90 | |||||
[39] | Soybean yield prediction | PLSR (M), RF (M), SVR (M), 2 types of DNN (M) | 1, 2, 4 | 0.72 | |||||
[52] | Crop monitoring | PLSR (M), RF (M), SVR (M), ELR (M) | 1, 2 | 0.60–0.93 | |||||
[40] | Evapotranspiration estimation | MSDF-ET (L) | 1, 2, 4 | ||||||
[ | |||||||||
94 | |||||||||
] | |||||||||
Rapid determination of soil class | |||||||||
Outer product analysis (L) | |||||||||
7 | |||||||||
0.65 | |||||||||
[ | |||||||||
16 | |||||||||
] | |||||||||
Navigation of autonomous vehicle | |||||||||
MSPI algorithm with Bayesian estimator (L) | |||||||||
11, 12 | |||||||||
N/A | |||||||||
[ | |||||||||
38 | |||||||||
] | |||||||||
Detection of cotton plants | |||||||||
Discriminant analysis (M) | |||||||||
2, 7 | |||||||||
0.97 | |||||||||
0.68–0.77 | |||||||||
[10] | Review: IoT and data fusion for crop disease | N/A | N/A | N/A | 75] | Delineation of homogeneous management zones | Kriging (L), Gaussian anamorphosis (L) | 9, 15 | N/A |
[102] | Arid and semi-arid land vegetation monitoring | Decision tree (L/M) | 3, 5 | 0.84–0.89 | [27] | ||||
[41] | Biomass and leaf nitrogen content in sugarcane | ||||||||
[ | |||||||||
95 | |||||||||
] | |||||||||
Map-based variable-rate manure application | |||||||||
K-means clustering (L) | 2, 9 | 0.60–0.93 | |||||||
[17] | Navigation of autonomous vehicles | Kalman filter (L) | 11, 12 | N/A | |||||
[96] | Robust tomato recognition for robotic harvesting | Wavelet transform (L) | 1 | 0.93 | |||||
[97] | Navigation of autonomous vehicle | Self-adaptive PCA, dynamic time warping (L) | 1, 11 | N/A | |||||
[98] | Recognition of wheat spikes | Gram–Schmidt fusion algorithm (L) | 1, 2 | 0.60–0.79 |
Ref. | Application | Fusion Technique | ||
---|---|---|---|---|
PCA and linear regression (L) | ||||
2, 5 | ||||
0.57 | ||||
[ | ||||
70 | ||||
] | ||||
Review: data fusion in agricultural systems | N/A | N/A | N/A | |
[103] | Navigation system for UAV | EKF (L) | 11, 12 | 0.98 |
[38] | Detection of cotton plants | Discriminant analysis (M) | 2 | 0.97 |
[71] | Vineyard monitoring | PLSR (M), SVR (M), RFR (M), ELR (M) | 2 | 0.98 |
Ref. | Application | Fusion Technique | Fused Data | Mean Accuracy |
---|---|---|---|---|
[42] | Soil moisture mapping | ESTARFM (L) | 2 | 0.70–0.84 |
[45] | Crop type mapping | 2D and 3D U-Net (L), SegNet (L), RF (L) | 2, 6 | 0.91–0.99 |
[43] | Estimation of surface soil moisture | ESTARFM (L) | 2 | 0.55–0.92 |
[26] | Delineation of homogeneous zones | Kriging and other geostatistical tools | 2, 9 | N/A |
[51] | Estimation of crop phenological states | Particle filter scheme (L/M) | 2, 6, 10 | 0.93–0.96 |
[53] | Evapotranspiration mapping at field scales | STARFM (L) | 2 | 0.92–0.95 |
[31] | In-field estimation of soil properties | RK (L), PLSR (L) | 3, 9 | >0.5 |
[59] | Estimation of wheat grain nitrogen uptake | BK (L) | 2, 3 | N/A |
[44] | Surface soil moisture monitoring | Linear regression analysis and Kriging (L/M) | 2, 15 | 0.51–0.84 |
[46] | Crop discrimination and classification | Voting system (H) | 2, 6 | 0.96 |
[9] | Review on multimodality and data fusion in RS | N/A | N/A | N/A |
[47] | Crop Mapping | Pixelwise matching (H) | 2, 6 | 0.94 |
[110] | Review on fusion between MODIS and Landsat | N/A | N/A | N/A |
[106] | Mapping crop progress | STARFM (L) | 2 | 0.54–0.86 |
[66] | Generation of spectral–-temporal response | Bayesian data imputation (L) | 2, 3 | 0.77–0.83 |
[28] | Delineation of management zones | K-means clustering (L) | 2, 9, 14 | N/A |
[114] | Mapping irrigated areas | Decision tree (L) | 2 | 0.67–0.93 |
[54] | Evapotranspiration mapping | Empirical exploration of band relationships (L) | 2, 4 | 0.20–0.97 |
[28] | Delineation of management zones | K-means clustering (L) | 2, 9, 14 | N/A |
[67] | Yield gap attribution in maize | Empirical equations (L) | 15 | 0.37–0.74 |
[63] | Change detection and biomass estimation in rice | Graph-based data fusion (L) | 2 | 0.17–0.90 |
[107] | Leaf area index estimation | STARFM (L) | 2 | 0.69–0.76 |
[55] | Evapotranspiration estimates | STARFM (M) | 2 | N/A |
[115] | Classification of agriculture drought | Optimal weighting of individual indices (M) | 2 | 0.80–0.92 |
[56] | Mapping daily evapotranspiration | STARFM (L) | 2 | N/A |
[20] | Mapping of cropping cycles | STARFM (L) | 2 | 0.88–0.91 |
[116] | Evapotranspiration partitioning at field scales | STARFM (L) | 2 | N/A |
[68] | Review: image fusion technology in agriculture | N/A | N/A | N/A |
[52] | Crop monitoring | PLSR (M), RF (M), SVR (M), ELR (M) | 1, 2, 4 | 0.60–0.93 |
[113] | Mapping of smallholder crop farming | XGBoost (L/M and H), RF (H), SVM (H), ANN (H), NB (H) | 2, 6 | 0.96–0.98 |
[64] | Estimation of biomass in grasslands | Simple quadratic combination (L/M) | 2, 15 | 0.66–0.88 |
[40] | Evapotranspiration estimation | MSDF-ET (L) | 1, 2, 4 | 0.68–0.77 |
[117 | ||||
[ | ||||
126 | ||||
] | ||||
Impact of tile drainage on evapotranspiration | ||||
STARFM (L) | ||||
2 | ||||
0.23–0.91 | ||||
[ | ||||
127 | ||||
] | ||||
Estimation of leaf area index | ||||
CACAO method (L) | ||||
2 | ||||
0.88 | ||||
[105] | Mapping winter wheat in urban region | SVM (M), RF (M) | 2, 6 | 0.98 |
No. | Classes of Data Fusion Technique | No. | Classes of Data Being Fused |
---|---|---|---|
1 |
Ref. | Application | Fusion Technique | Fused Data | Mean Accuracy | |||||
---|---|---|---|---|---|---|---|---|---|
[30] | Estimation of soil indices | SF (L), MOA (H) | 7 | 0.80–0.90 | |||||
[73] | Sustainable greenhouse management | Decision rules (L) | 10 | N/A | |||||
[72] | Human—robot interaction | LSTM-NN (L) | 11 | 0.71–0.97 | |||||
[25] | Delineation of homogeneous zones in viticulture | GAN (L), geostatistical tools (L) | 2, 9 | N/A | |||||
[26] | Delineation of homogeneous zones | Kriging and other geostatistical tools (L) | 2, 9 | N/A | |||||
[51] | Estimation of crop phenological states | Particle filter scheme (L) | 2, 6, 10 | 0.93–0.96 | |||||
[18] | Fruit detection | LPT (L) and fuzzy logic (L) | 1, 4 | 0.80–0.95 | |||||
[31] | In-field estimation of soil properties | RK (L), PLSR (L) | 3, 9 | >0.5 | |||||
[74] | Delineation of homogeneous management zones | Kriging (L), Gaussian anamorphosis (L) | 9, 15 | 0.66 | |||||
[ | |||||||||
Delineation of homogeneous management zones | Kriging (L),Gaussian anamorphosis (L) | 9, 15 | N/A | ||||||
[76] | Crop nutritional status determination | PCA (L) | 7, 8 | 0.7–0.9 | |||||
[22] | Detection of olive quick decline syndrome | CNN (M) | 1 | 0.986 | |||||
[65] | Monitoring Agricultural Terraces | Coregistering and information extraction (L/M) | 5 | N/A | |||||
[77] | Prediction of canopy water content of rice | BPNN (M), RF (M), PLSR (M) | 2 | 0.98–1.00 | |||||
[11] | Localization of a wheeled mobile robot | Dempster–Shafer (L) and Kalman filter (L) | 11, 12 | 0.97 | |||||
[19] | Immature green citrus fruit detection | Color-thermal probability algorithm (H) | 1, 4 | 0.90–0.95 | |||||
[28] | Delineation of management zones | K-means clustering (L) | 2, 9, 14 | N/A | |||||
[78] | Segmentation for targeted application of products | Discrete wavelets transform (M) | 1 | 0.92 | |||||
[12] | System for agricultural vehicle positioning | Kalman filter (L) | 11, 12 | N/A | |||||
[13] | System for agricultural vehicle positioning | Kalman filter (L) | 11, 12 | N/A | |||||
[67] | Yield gap attribution in maize | Empirical equations (L) | 15 | 0.37–0.74 | |||||
[32] | Soil environmental quality assessment | Analytic hierarchy process, weighted average (L) | 15 | N/A | |||||
[33] | Predict soil properties | PLSR (L) | 7, 9, 13 | 0.80–0.96 | |||||
[14] | System for agricultural vehicle positioning | Discrete Kalman filter (L) | 11, 13 | N/A | |||||
[34] | Estimating soil macronutrients | PLSR (L) | 7, 9 | 0.70–0.95 | |||||
[20] | Citrus fruit detection and localization | Daubechies wavelet transform (L) | 1, 2 | 0.91 | |||||
[15] | Estimation of agricultural equipment roll angle | Kalman filtering (L) | 11 | N/A | |||||
[79] | Predicting toxic elements in the soil | PLSR, PCA, and SPA (L/M) | 7, 8 | 0.93–0.98 | |||||
[68] | Review: image fusion technology in agriculture | N/A | N/A | N/A | |||||
[80] | Heterogeneous sensor data fusion | Deep multimodal encoder (L) | 10 | N/A | |||||
[81] | Agricultural vulnerability assessments | Binary relevance (L), RF (L), and XGBoost (L) | 10,14 | 0.67–0.98 | |||||
[35] | Prediction of multiple soil properties | ] | Semantic segmentation of land typesSMLR (L), PLSR (L), PCA/SMLR combination (L) | 7, 9 | 0.60–0.95 | ||||
Majority rule (H) | 2 | 0.99 | [82] | Prediction of environment variables | Sparse model (L), LR (L), SVM (L), ELM (L) | 10 | 0.96 | ||
[ | |||||||||
[118] | Eucalyptus trees identification | Fuzzy information fusion (L) | 2 | 0.98 | 64] | ||||
[ | Estimation of biomass in grasslands | 10 | Simple quadratic combination (L) | ] | Review: IoT and data fusion for crop disease | N/A2, 15 | 0.66–0.88 | ||
N/A | N/A | [23] | |||||||
[69] | Plant disease detection | Kohonen self-organizing maps (M) | 3, 8 | 0.95 | |||||
Wheat yield prediction | CP-ANN (M), XY-fused networks (M), SKN (M) | 2, 7 | 0.82 | [83] | Water stress detection | ||||
[112] | Least squares support vectors machine (M) | 3, 8 | 0.99 | ||||||
Drought monitoring | RF (M) | 2, 15 | 0.29–0.77 | [84] | Delineation of water holding capacity zones | ANN (L), MLR (L) | |||
[48] | 7, 9 | 0.94–0.97 | |||||||
Crop type classification and mapping | RF (L) | 2, 6, 13 | 0.37–0.94 | [85] | Potential of site-specific seeding (potato) | ||||
[119 | PLSR (L) | ] | Time series data fusion2, 9 | 0.64–0.90 | |||||
Environmental data acquisition module | 10 | N/A | [86] | ||||||
[ | 3D characterization of fruit trees | 57 | Pixel level mapping between the images (L) | ] | Evapotranspiration prediction in vineyard | STARFM (L)4, 5 | N/A | ||
2 | 0.77–0.81 | [87] | |||||||
[108] | Measurements of sprayer boom movements | Summations of normalized measurements (L) | 11 | Daily NDVI product at a 30-m spatial resolution | GKSFM (M)N/A | ||||
2 | 0.88 | [10] | Review: IoT and data fusion for crop disease | N/A | N/A | N/A | |||
[49 | [88] | Prediction of wheat yield and protein | Canonical powered partial least-squares (L) | 7, 10 | 0.76–0.94 | ||||
] | Crop classification | Committee of MLPs (L) | 2, 6 | 0.65–0.99 | |||||
[6] | Multisource classification of remotely sensed data | Bayesian formulation (L) | 2, 6 | 0.74 | [69] | Wheat yield prediction | |||
[111 | CP-ANN (L), XY-fused networks (L), SKN (L) | ] | Fractional vegetation cover estimation2, 7 | 0.82 | |||||
Data fusion and vegetation growth models (L) | 2 | 0.83–0.95 | [89] | Topsoil clay mapping | PLSR (L) and kNN (L) | ||||
[120] | Land cover monitoring | FARMA (L) | 7, 9, 13 | 0.94–0.96 | |||||
2, 6 | N/A | [21] | |||||||
[121] | Fruit detection | CNN (L); scoring system (H) | 1, 2 | Crop ensemble classification | mosaicking (L), classifier majority voting (H)0.84 | ||||
2 | [37] | 3D reconstruction for agriculture phenotyping | Linear interpolation (L) | 1, 10 | N/A | ||||
0.82–0.85 | |||||||||
[70] | Review: data fusion in agricultural systems | N/A | N/A | N/A | [29] | Delineation of site-specific management zones | CoKriging (L) | ||
[50] | 2 | 0.55–0.77 | |||||||
In-season mapping of crop type | Classification tree (M) | 2 | 0.93–0.99 | [90] | Orchard mapping and mobile robot localization | ||||
[122 | Laser data projection onto the RGB images (L) | ] | Building frequent landsat-like imagery1, 5 | 0.97 | |||||
STARFM (L) | 2 | 0.63–0.99 | [24] | Modelling crop disease severity | 2 ANN architectures (L) | ||||
[58] | Evapotranspiration mapping | SADFAET (M) | 10, 15 | 0.90–0.98 | |||||
2 | N/A | [91] | |||||||
[123] | Tropical soil fertility analysis | SVM (L), PLS (L), least squares modeling (L) | 2, 8 | 0.30–0.95 | |||||
Temporal land use mapping | Dynamic decision tree (M) | 2 | [92] | Internet of things applied to agriculture | Hydra system (L/M/H) | 9, 10, 15 | 0.93–0.99 | ||
0.86–0.96 | [70] | Review: data fusion in agricultural systems | N/A | ||||||
[124 | N/A | N/A | |||||||
] | High-resolution leaf area index estimation | STDFA (L) | 2 | 0.98 | |||||
[125] | Monitoring cotton root rot | ISTDFA (M) | 2 | 0.79–0.97 | [36] | Soil health assessment | PLSR (L) | 7, 9 | 0.78 |
[ | |||||||||
[109] | Monitoring crop water content | Modified STARFM (L) | 2 | 0.44–0.85 | 93] | Prediction of Soil Texture | SMLR (L), PLSR (L) and PCA (L) | ||
[104 | 7, 8 | ] | Soil moisture content estimation | Vector concatenation, followed by ANN (M)0.61–0.88 | 2, 6 | 0.39–0.93 | |||
[128] | Leaf area index estimation | ESTARFM (L), linear regression model (M) | 2 | 0.37–0.95 | |||||
[71] | Vineyard monitoring | PLSR (M), SVR (M), RFR (M), ELR (M) | 2 | 0.98 |
Regression methods | 1 | RGB images | |
2 | STARFM-like statistical methods | 2 | Multispectral images |
3 | Geostatistical tools | 3 | Hyperspectral images |
4 | PCA and derivatives | 4 | Thermal images |
5 | Kalman filter | 5 | Laser scanning |
6 | Machine learning | 6 | SAR images |
7 | Deep learning | 7 | Spectroscopy |
8 | Decision rules | 8 | Fluorescence images |
9 | Majority rules | 9 | Soil measurements |
10 | Model output averaging | 10 | Environmental/weather measurements |
11 | Others | 11 | Inertial measurements |
12 | Position measurements | ||
13 | Topographic records and elevation models | ||
14 | Historical data | ||
15 | Others |