Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars
Lettuce is an important vegetable in the human diet and is commonly consumed for salad. It is a source of vitamin A, which plays a vital role in human health. Improvements in lettuce production will be needed to ensure a stable and economically available supply in the future. The influence of nitrog...
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| Format: | Article |
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MDPI AG
2022-10-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/21/8158 |
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| author | Sulaymon Eshkabilov John Stenger Elizabeth N. Knutson Erdem Küçüktopcu Halis Simsek Chiwon W. Lee |
| author_facet | Sulaymon Eshkabilov John Stenger Elizabeth N. Knutson Erdem Küçüktopcu Halis Simsek Chiwon W. Lee |
| author_sort | Sulaymon Eshkabilov |
| collection | DOAJ |
| description | Lettuce is an important vegetable in the human diet and is commonly consumed for salad. It is a source of vitamin A, which plays a vital role in human health. Improvements in lettuce production will be needed to ensure a stable and economically available supply in the future. The influence of nitrogen (N), phosphorus (P), and potassium (K) compounds on the growth dynamics of four hydroponically grown lettuce (<i>Lactuca sativa</i> L.) cultivars (Black Seeded Simpson, Parris Island, Rex RZ, and Tacitus) in tubs and in a nutrient film technique (NFT) system were studied. Hyperspectral images (HSI) were captured at plant harvest. Models developed from the HSI data were used to estimate nutrient levels of leaf tissues by employing principal component analysis (PCA), partial least squares regression (PLSR), multivariate regression, and variable importance projection (VIP) methods. The optimal wavebands were found in six regions, including 390.57–438.02, 497–550, 551–600, 681.34–774, 802–821, and 822–838 nm for tub-grown lettuces and four regions, namely 390.57–438.02, 497–550, 551–600, and 681.34–774 nm for NFT-system-grown lettuces. These fitted models’ levels showed high accuracy <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo stretchy="false">(</mo><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.85</mn><mo>−</mo><mn>0.99</mn><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> in estimating the growth dynamics of the studied lettuce cultivars in terms of nutrient content. HSI data of the lettuce leaves and applied N solutions demonstrated a direct positive correlation with an accuracy of 0.82–0.99 for blue and green regions in 400–575 nm wavebands. The results proved that, in most of the tested multivariate regression models, HSI data of freshly cut leaves correlated well with laboratory-measured data. |
| first_indexed | 2024-03-09T18:40:41Z |
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| id | doaj.art-0466cdd10a4d404bb8d6e3ee363b37f9 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
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| publishDate | 2022-10-01 |
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| spelling | doaj.art-0466cdd10a4d404bb8d6e3ee363b37f92023-11-24T06:43:38ZengMDPI AGSensors1424-82202022-10-012221815810.3390/s22218158Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) CultivarsSulaymon Eshkabilov0John Stenger1Elizabeth N. Knutson2Erdem Küçüktopcu3Halis Simsek4Chiwon W. Lee5Department of Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND 58108, USADepartment of Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND 58108, USADepartment of Plant Sciences, North Dakota State University, Fargo, ND 58108, USADepartment of Agricultural Structures and Irrigation, Ondokuz Mayıs University, Samsun 55139, TurkeyDepartment of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USADepartment of Plant Sciences, North Dakota State University, Fargo, ND 58108, USALettuce is an important vegetable in the human diet and is commonly consumed for salad. It is a source of vitamin A, which plays a vital role in human health. Improvements in lettuce production will be needed to ensure a stable and economically available supply in the future. The influence of nitrogen (N), phosphorus (P), and potassium (K) compounds on the growth dynamics of four hydroponically grown lettuce (<i>Lactuca sativa</i> L.) cultivars (Black Seeded Simpson, Parris Island, Rex RZ, and Tacitus) in tubs and in a nutrient film technique (NFT) system were studied. Hyperspectral images (HSI) were captured at plant harvest. Models developed from the HSI data were used to estimate nutrient levels of leaf tissues by employing principal component analysis (PCA), partial least squares regression (PLSR), multivariate regression, and variable importance projection (VIP) methods. The optimal wavebands were found in six regions, including 390.57–438.02, 497–550, 551–600, 681.34–774, 802–821, and 822–838 nm for tub-grown lettuces and four regions, namely 390.57–438.02, 497–550, 551–600, and 681.34–774 nm for NFT-system-grown lettuces. These fitted models’ levels showed high accuracy <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo stretchy="false">(</mo><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.85</mn><mo>−</mo><mn>0.99</mn><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> in estimating the growth dynamics of the studied lettuce cultivars in terms of nutrient content. HSI data of the lettuce leaves and applied N solutions demonstrated a direct positive correlation with an accuracy of 0.82–0.99 for blue and green regions in 400–575 nm wavebands. The results proved that, in most of the tested multivariate regression models, HSI data of freshly cut leaves correlated well with laboratory-measured data.https://www.mdpi.com/1424-8220/22/21/8158lettucehyper-spectral imagingnutrient levelreflectancespectral indexpartial least squares regression |
| spellingShingle | Sulaymon Eshkabilov John Stenger Elizabeth N. Knutson Erdem Küçüktopcu Halis Simsek Chiwon W. Lee Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars Sensors lettuce hyper-spectral imaging nutrient level reflectance spectral index partial least squares regression |
| title | Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars |
| title_full | Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars |
| title_fullStr | Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars |
| title_full_unstemmed | Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars |
| title_short | Hyperspectral Image Data and Waveband Indexing Methods to Estimate Nutrient Concentration on Lettuce (<i>Lactuca sativa</i> L.) Cultivars |
| title_sort | hyperspectral image data and waveband indexing methods to estimate nutrient concentration on lettuce i lactuca sativa i l cultivars |
| topic | lettuce hyper-spectral imaging nutrient level reflectance spectral index partial least squares regression |
| url | https://www.mdpi.com/1424-8220/22/21/8158 |
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