Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
Abstract
1. Introduction
2. Materials and Methods
2.1. Overview of the Pilot Study Area
2.2. Research Methodology
2.2.1. Pear Tree Canopy Sample Collection
2.2.2. Spectroscopy and Determination of the Relative Chlorophyll Content
2.2.3. Processing of Spectral Data
2.2.4. Construction of a Model for Estimating the SPAD Value of Pear Leaves and Validation of Model Accuracy
3. Results
3.1. Correlation Between the Traditional Mathematically Transformed Spectra and the SPAD Value of Pear Leaves
3.2. Correlation of Discrete Wavelet Transformed Spectra with SPAD Value of Pear Leaves
3.3. A Model for Estimating the SPAD Value of Pear Leaves
3.3.1. Constructing a Model for Estimating the SPAD Value of Pear Leaves Based on Mathematical Transformations
3.3.2. Construction of a Diagnostic Model for Estimating the SPAD Value of Pear Leaves Based on the Discrete Wavelet Transform
3.4. Comparative Analysis of Relative Chlorophyll Content Regression Models for Pear Leaves
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Statistical Parameter | Number of Samples | Minimum Value | Maximum Value | Average Value | Standard Deviation | RMSE | Coefficient of Variation (CV) |
---|---|---|---|---|---|---|---|
SPAD value | 87 | 32.6 | 67.1 | 45.8 | 3.64 | 46.9 | 7.95% |
Transformation Form | Sensitive Band (nm) | Model | Training | Validating | ||
---|---|---|---|---|---|---|
R2 | RMSE | R2 | RMSE | |||
Original spectrum/R | 455, 632 | y = −0.777 + 0.002x455 + 0.003x632 | 0.779 | 1.406 | 0.363 | 0.962 |
Inverse transformation 1/R | 501, 714 | y = −0.108 + 0.013x501 + 0.038x714 | 0.651 | 1.244 | 0.697 | 1.357 |
Logarithmic transformation logR | 472, 721 | y = −1.796 + 0.037x472 + 0.021x721 | 0.696 | 1.095 | 0.861 | 0.738 |
First-order differential transform R′ | 847, 976 | y = 0.004 − 0.042x847 + 0.003x976 | 0.834 | 1.821 | 0.785 | 1.172 |
First-order differential transform of the inverse (1/R)′ | 834, 998 | y = −0.011 − 0.069x834 + 0.011x998 | 0.741 | 1.165 | 0.658 | 1.279 |
First-order differential transform of the logarithm (logR)′ | 825, 1034 | y = 0.002 − 0.062x825 − 0.014x1034 | 0.063 | 1.986 | 0.885 | 1.925 |
Transformation Form | Sensitive Band (nm) | Model | Training | Validating | ||
---|---|---|---|---|---|---|
R2 | RMSE | R2 | RMSE | |||
H1 | 474, 791 | y = −0.001 − 0.032x474 + 0.018x791 | 0.415 | 1.584 | 0.478 | 1.661 |
H2 | 476, 814 | y = 0.013 − 0.052x476 + 0.059x814 | 0.527 | 1.942 | 0.473 | 2.205 |
H3 | 485, 873 | y = 0.005 − 0.027x485 + 0.203x873 | 0.337 | 1.672 | 0.235 | 1.389 |
L1 | 516, 724 | y = 0.057 − 0.851x516 + 0.073x724 | 0.742 | 0.936 | 0.647 | 1.247 |
L2 | 534, 726 | y = 0.551 − 0.861x534 + 0.105x726 | 0.269 | 1.468 | 0.439 | 1.683 |
L3 | 498, 714 | y = −0.544 + 0.867x498 + 0.107x714 | 0.491 | 1.572 | 0.573 | 1.891 |
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Huang, Y.; Fan, Z.; Wu, H.; Zhang, X.; Liu, Y. Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang. Sensors 2025, 25, 3552. https://doi.org/10.3390/s25113552
Huang Y, Fan Z, Wu H, Zhang X, Liu Y. Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang. Sensors. 2025; 25(11):3552. https://doi.org/10.3390/s25113552
Chicago/Turabian StyleHuang, Yufen, Zhenqi Fan, Hongxin Wu, Ximeng Zhang, and Yanlong Liu. 2025. "Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang" Sensors 25, no. 11: 3552. https://doi.org/10.3390/s25113552
APA StyleHuang, Y., Fan, Z., Wu, H., Zhang, X., & Liu, Y. (2025). Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang. Sensors, 25(11), 3552. https://doi.org/10.3390/s25113552