Laser & Optoelectronics Progress, Volume. 60, Issue 7, 0730005(2023)
Fractional Differential-Based Hyperspectral Inversion of Soil Organic Matter Content
Figures & Tables(7)
Fig. 3. Correlation coefficient between SOM content and spectral reflectance transform form. (a) 1-order differential; (b) 1.2-order differential; (c) 1.4-order differential; (d) 1.6-order differential; (e) 1.8-order differential; (f) 2-order differential
Fig. 4. Optimal mathematical transformation form of SOM results in the three models. (a) 1-order differential of SVR model; (b) 1-order differential of PLSR model; (c) 1.2-order differential of RF model
Table 1. SOM content statistical characteristics of study area samples
View tableTable 1. SOM content statistical characteristics of study area samples
Sample type Quantity Max Min Mean Standard deviation CV /% Calibration 49 25.416 2.758 11.602 5.436 46.86 Validation 24 24.133 2.742 12.531 5.810 46.37 Totality 73 25.416 2.742 11.959 5.601 46.84
Table 2. Characteristic bands of SOM under fractional differentiation
View tableTable 2. Characteristic bands of SOM under fractional differentiation
Spectral transformation Characteristic band /nm Number of wavelengths r 0 / 0 / 0.2 / 0 / 0.4 / 0 / 0.6 / 0 / 0.8 399、435 2 0.293、0.316 1 588、597、630、648、675、792、855、1013 8 0.308、0.323、0.290、-0.286、-0.308、-0.350、-0.291、0.290 1.2 407、464、588、597、648、671、675、723、792、1013 10 0.285、-0.312、0.290、0.319、-0.310、0.280、-0.287、-0.293、-0.368、0.353 1.4 407、425、464、597、648、671、723、775、792、965、1013 11 0.316、-0.294、-0.335、0.315、-0.308、0.287、-0.307、0.282、-0.372、-0.278、0.283 1.6 387、407、425、464、597、648、671、676、723、775、792、965 12 0.296、0.343、-0.283、-0.343、0.305、-0.300、0.285、0.278、-0.311、0.298、-0.366、-0.278 1.8 387、407、464、597、648、671、676、723、775、792、797 11 0.309、0.364、-0.347、0.288、-0.291、0.278、0.289、-0.307、0.309、-0.353、0.277 2 387、407、464、648、676、723、775、792、797 9 0.303、0.377、-0.349、-0.282、0.293、-0.297、0.314、-0.336、0.278
Table 3. SOM content modeling and validation results
View tableTable 3. SOM content modeling and validation results
Model Sample type Model formula R2 RMSE RPD SVR—1 Calibration set y=0.76x+2.8583 0.83 2.29 2.43 SVR—1.2 y=0.7074x+3.5983 0.73 2.84 1.96 SVR—1.4 y=0.6341x+4.7963 0.67 3.19 1.74 SVR—1.6 y=0.7051x+3.9563 0.71 3.01 1.85 SVR—1.8 y=0.7537x+2.777 0.81 2.45 2.27 SVR—2 y=0.7488x+2.5789 0.81 2.48 4.97 SVR—1 Validation set y=0.777x+3.0056 0.82 1.75 3.38 SVR—1.2 y=0.8659x+1.9667 0.93 1.13 5.21 SVR—1.4 y=0.897x+1.4525 0.97 0.79 7.52 SVR—1.6 y=0.9153x+1.274 0.97 0.76 7.75 SVR—1.8 y=0.9031x+1.5441 0.96 0.86 6.83 SVR—2 y=0.8639x+2.2584 0.93 1.19 3.73 PLSR—1 Calibration set y=0.5492x+5.3037 0.55 4.24 1.31 PLSR—1.2 y=0.4062x+6.9854 0.41 4.24 1.30 PLSR—1.4 y=0.3676x+7.4394 0.37 4.37 1.27 PLSR—1.6 y=0.3553x+7.5838 0.36 4.42 1.26 PLSR—1.8 y=0.3697x+7.415 0.37 4.37 1.27 PLSR—2 y=0.3697x+7.4153 0.37 4.37 1.05 PLSR—1 Validation set y=0.6591x+4.2127 0.71 2.18 2.71 PLSR—1.2 y=0.7094x+3.5908 0.71 3.12 1.86 PLSR—1.4 y=0.6275x+4.6023 0.63 2.47 2.39 PLSR—1.6 y=0.65x+4.3244 0.65 2.39 2.47 PLSR—1.8 y=0.6028x+4.9078 0.60 2.55 2.32 PLSR—2 y=0.6137x+4.7739 0.61 2.52 2.09 RF—1 Calibration set
y=0.6285x+4.3153 0.82 2.61 2.13 RF—1.2 y=0.5551x+5.2584 0.92 2.60 2.14 RF—1.4 y=0.5674x+5.1131 0.91 2.58 2.16 RF—1.6 y=0.5544x+5.2686 0.88 2.70 2.06 RF—1.8 y=0.5864x+4.9469 0.91 2.50 2.22 RF—2 y=0.6319x+4.7115 0.80 2.71 2.05 RF—1 Validation set y=0.5873x+5.0345 0.79 2.07 2.85 RF—1.2 y=0.6418x+4.4054 0.93 1.62 3.65 RF—1.4 y=0.604x+4.953 0.92 1.77 3.34 RF—1.6 y=0.5824x+5.2598 0.90 1.87 3.16 RF—1.8 y=0.5654x+5.4647 0.90 1.93 3.07 RF—2 y=0.6048x+4.639 0.86 1.88 3.14
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Wuyao Li, Mamat Sawut, Maihemuti Balati. Fractional Differential-Based Hyperspectral Inversion of Soil Organic Matter Content[J]. Laser & Optoelectronics Progress, 2023, 60(7): 0730005
Paper Information
Category: Spectroscopy
Received: Feb. 14, 2022
Accepted: Mar. 18, 2022
Published Online: May. 24, 2023
The Author Email: Sawut Mamat (korxat@xju.edu.cn)
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