Plant Water Content Detection Using Dual Near-Infrared Beams
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Solution Overview
Problem
Farmers face challenges in quantitatively and time-serially monitoring water content in plants without relying on experiences or visual observations, making it difficult to detect early signs of water stress and partial necrosis in crops.
Innovation Solution
A device comprising a plant detection camera that uses near-infrared laser beams of different wavelengths to measure water content in plants, providing a water content index through the intensity ratio of diffuse reflection light, and a cultivation controller for irrigation management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If farmers visually observe leaves to determine water content, then the method is simple and requires no special equipment, but the measurement is subjective and cannot quantitatively detect early water stress
Solution Approach 1:
The patent replaces the mechanical/visual observation system with an optical measurement system. Specifically, it uses near-infrared and short-wave infrared sensors to detect light absorption characteristics of plant leaves, converting subjective visual assessment into objective quantitative data. The system measures reflectance or transmittance of infrared light through the leaf, which correlates with water content, thereby eliminating the need for farmer expertise while providing precise measurements.
Solution Approach 2:
The patent introduces an intermediary optical measurement system between the farmer and the plant. Instead of directly observing the plant, the system uses infrared sensors as intermediaries to detect water content. This intermediary device captures optical signals from the plant and converts them into quantifiable water content data, enabling early detection of water stress before visible symptoms appear.
2Loss of time
If farmers wait for visible symptoms to appear, then no special equipment is needed, but water stress and partial necrosis are detected too late for effective intervention
Solution Approach 1:
The patent implements preliminary detection by measuring infrared light absorption properties of leaves before visible water stress symptoms manifest. The system continuously or periodically monitors water content indices and compares them against threshold values, enabling early warning of water stress conditions. This preliminary action allows farmers to intervene before partial necrosis occurs, preventing crop damage rather than reacting to it.
Solution Approach 2:
The patent establishes a feedback mechanism where water content measurements are continuously monitored and compared against predetermined thresholds. When the water content index falls below the threshold indicating water stress, the system provides feedback to alert farmers. This feedback loop enables timely intervention by notifying farmers of water stress conditions before visible damage occurs, allowing corrective irrigation actions to prevent partial necrosis.
3Measurement precision
If multiple measurement points are taken to ensure accuracy, then measurement precision improves, but the time required for observation and the complexity of data collection increase
Solution Approach 1:
The patent replaces manual multi-point measurement with an automated optical scanning system. The infrared sensors can rapidly scan multiple locations on the plant or even entire fields, capturing water content data from numerous points simultaneously or in quick succession. This automated optical system processes all measurements and generates average water content indices without requiring farmer involvement in the actual measurement process, thereby maintaining high precision while minimizing time investment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate, quantitative monitoring of water content and early detection of water stress and partial necrosis, allowing for timely irrigation adjustments and improved crop health.
Implementation Method 1
receives diffuse reflection light RV1 and RV2 that are reflected on irradiation positions of plant PT
Implementation Method 2
radiates reference beam LS1 and measuring beam LS2 that are near-infrared laser beams
Implementation Method 3
measuring beam LS2 that has a wavelength of 1550 nm, which has a characteristic in which light is easily absorbed in water
Data Source
Figure 1
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Figure 3
AI summary
A first beam source radiates, as a reference beam, 905 nm of near infrared beam having a characteristic in which light tends not to be absorbed in water toward a leaf of a plant. A second beam source radiates, as a measuring beam, 1550 nm of near infrared beam having a characteristic in which light tends to be absorbed in water toward the leaf of the plant. A threshold level setter / water content index detector calculates a water content index of one leaf which is a total sum ∑Ln (I905/I1550) of the reflection intensity ratio. A controller displays a graph representing a total sum of water content of the leaf and a pixel average value as a time-transition of the water content contained in the plant from the start of the measurement period on a UI screen of a monitor. When viewed from first beam source and second beam source, white reference substrate which covers a back surface of the leaf of the plant is disposed on the leaf of the plant.