Phase Delay Plant Detection System

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Solution Overview

Problem

Current plant detection systems face challenges in accurately differentiating between plants and bare soil, leading to potential false detections and unnecessary herbicide application.

Innovation Solution

The method involves adjusting the intensities of light beams at different wavelengths to achieve a phase delay of the composite light beam that is approximately halfway between the phase delays for bare soil and plants, allowing for improved detection sensitivity and reduced false positives by setting a plant detection phase delay based on measured soil and plant phase delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light beam intensities are not adjusted, then the detection system is simpler to operate, but the detection sensitivity and accuracy deteriorate due to false detections between plants and bare soil

Engineering Contradiction:
Improvedetection accuracyVSAvoidsystem operation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs preliminary calibration by measuring phase delays for both bare soil and plants before actual detection. These measured values are stored and used to automatically set the detection threshold, eliminating the need for manual adjustment and ensuring optimal detection accuracy without increasing operational complexity during field use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the detection parameter from simple intensity comparison to phase delay measurement. By measuring the phase delay of the composite signal and comparing it against calibrated values, the system achieves higher detection accuracy and reduces false positives between plants and bare soil.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a fixed detection threshold is used, then the system is easier to control, but false detections increase due to varying environmental conditions

Engineering Contradiction:
Improvedetection reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system incorporates feedback by measuring the actual phase delay values during operation and comparing them against the calibrated reference values. This feedback mechanism allows the system to adapt to varying environmental conditions and maintain high detection reliability without requiring complex real-time control adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The detection threshold is pre-determined through calibration measurements of bare soil and plants. This preliminary action creates a reference framework that simplifies ongoing control operations while maintaining high reliability across varying environmental conditions.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If herbicide is sprayed without detection, then productivity is higher, but herbicide waste increases on bare soil

Engineering Contradiction:
Improvespraying efficiencyVSAvoidherbicide waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The invention replaces manual or blanket mechanical spraying with an optically-controlled system. By using optical detection of phase delay to identify plants versus bare soil, the system enables precise control of herbicide application, maintaining productivity while eliminating waste on bare soil areas.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach enhances the sensitivity and accuracy of plant detection, reducing false detections and optimizing herbicide application by adjusting light beam intensities to achieve a balanced phase delay, thereby improving system performance.

Implementation Method 1

The spectral reflectance of a plant compared to that of soil can be used to detect the presence of a plant on the ground

Methodology Applied
Scientific EffectSpectral reflectance: Reflection

Implementation Method 2

the intensities of the different wavelengths of scattered light returning from the ground can be compared to determine if there is a plant or just bare soil

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

an active filter and a resonant circuit. The resonant circuit is an inductor/capacitor circuit that tunes the active filter

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3639660B1Controlling plant detection systems
Publication Date: 2023.09.06 TRIMBLE INC
  • EP3639660B1 patent drawingFigure 1
  • EP3639660B1 patent drawingFigure 2
  • EP3639660B1 patent drawingFigure 3

AI summary

Methods for controlling a plant detection system include determining a target phase delay based on a first phase delay of reflected portions of a first light beam and a second phase delay of reflected portions of a second light beam. A composite light beam comprising the first light beam and the second light beam is emitted towards bare soil, and reflected portions of the composite light beam are detected. An intensity of at least one of the first light beam or the second light beam is adjusted so that a phase delay of the composite light beam is approximately equal to the target phase delay.