Multi-Wavelength Plant Discrimination Sensor
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Solution Overview
Problem
Current sensor systems for discriminating objects, particularly in agriculture, face challenges in accurately identifying plants in real-time and at operational speeds due to issues with light focusing and reliability in differentiating between green plants, especially when the target object varies in distance from the light source.
Innovation Solution
A sensing system utilizing a light source with multiple distinct wavelengths to illuminate a field of view, a sensor to measure reflectance at each wavelength, and an identifier to determine object identification by calculating ratios between measured reflectances, along with a multiple beam light source and collimator to ensure accurate and reliable discrimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wavelength light source is used, then the device complexity is reduced, but the measurement precision for discriminating between different green plants deteriorates
Solution Approach 1:
The light source is segmented into multiple independent wavelength channels (red, green, blue LEDs) that can be controlled separately. Each wavelength provides specific spectral information about plant characteristics, enabling accurate discrimination between different plant types while maintaining manageable device complexity through modular LED architecture.
Solution Approach 2:
The system changes the wavelength parameter by switching between different LED types (red 660nm, green 530nm, blue 480nm). This allows the system to probe different spectral reflection characteristics of plants at various growth stages, improving measurement precision without requiring a single complex light source.
2Measurement precision
If the light source focuses light at a fixed distance, then the measurement precision at that distance is improved, but the adaptability to varying target distances deteriorates
Solution Approach 1:
The system employs dynamic control of LED illumination intensity and wavelength selection based on the detected distance of the target object. As the target distance varies, the controller adjusts the illumination parameters in real-time to maintain optimal measurement conditions, ensuring both precision and adaptability across different distances.
Solution Approach 2:
The system uses feedback from the sensor about target distance and reflectance characteristics to dynamically adjust the light source output. This closed-loop control allows the system to compensate for distance variations and maintain measurement precision across the entire operating range.
3Measurement precision
If multiple wavelengths are used simultaneously, then the measurement precision for plant discrimination is improved, but the device complexity and energy consumption increase
Solution Approach 1:
The system uses periodic action by sequentially activating different wavelength LED groups rather than all wavelengths simultaneously. The controller activates specific wavelength combinations based on the measurement requirements and target characteristics, reducing overall energy consumption while maintaining the ability to extract comprehensive spectral information for accurate plant discrimination.
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
The system effectively discriminates between different types of green plants and reduces environmental chemical usage by enabling site-specific application of herbicides, improving accuracy and reducing farm costs through real-time identification and precise targeting.
Implementation Method 1
a light source having three or more distinct wavelengths for illuminating a plurality of distinct areas in a field of view
Implementation Method 2
a sensor for measuring the reflectance of the distinct areas at each of the distinct wavelengths
Data Source
AI summary
A sensing system comprises a light source having three or more distinct wavelengths for illuminating a plurality of distinct areas in a field of view, a sensor for measuring the reflectance of the distinct areas at each of the distinct wavelengths, and an identifier for identifying at least one object in the field of view from the measured reflectance at each of the wavelengths.