UAV Multispectral Chlorophyll Monitoring for Summer Maize Drought

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Solution Overview

Problem

Current methods for drought monitoring in summer maize are labor-intensive, time-consuming, and lack precision, particularly in defining chlorophyll content thresholds for different drought levels, which hampers efficient and accurate irrigation practices.

Innovation Solution

A rapid UAV-based method using multispectral imagery and chlorophyll content analysis, involving data acquisition, construction of chlorophyll content inversion models, calibration of thresholds, and real-time discrimination of drought severity levels through NDVI, RENDVI, and SAVI indices, optimized for different growth stages of summer maize.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual observation methods are used to monitor vegetation parameters, then detailed physiological parameter data can be obtained, but the process becomes time-consuming, labor-intensive, and damages plants

Engineering Contradiction:
Improvephysiological parameter data accuracyVSAvoidmonitoring time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical observation with UAV-based optical remote sensing technology. The UAV captures multispectral imagery of the maize field, and chlorophyll content is extracted through spectral analysis algorithms, eliminating the need for physical plant handling and manual measurement while maintaining measurement precision.

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

Solution Approach 2:

The patent creates a remote sensing copy of the vegetation physiological state by capturing spectral signatures that correlate with chlorophyll content. This optical copy allows monitoring without physical contact, preventing plant damage while providing detailed physiological data through spectral analysis.

Inventive Principle:
Principle #26Copying

2Measurement precision

If traditional soil moisture monitoring methods are used, then drought assessment can be performed, but the process is labor-intensive and lacks precision

Engineering Contradiction:
Improvedrought monitoring accuracyVSAvoidmonitoring efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical soil moisture sampling with UAV-based optical remote sensing. Multispectral imagery captures vegetation reflectance characteristics, and chlorophyll content is inverted through spectral models, providing precise drought assessment across large areas without manual fieldwork.

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

Solution Approach 2:

The UAV-based chlorophyll monitoring system serves multiple functions: it assesses vegetation health, monitors drought conditions, evaluates irrigation effectiveness, and tracks crop growth stages simultaneously, greatly enhancing monitoring productivity compared to specialized traditional methods.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If satellite remote sensing is used for large-area drought monitoring, then broad coverage is achieved, but spatial resolution and temporal continuity are reduced

Engineering Contradiction:
Improvemonitoring coverage areaVSAvoidspatial resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent transitions from space-based satellite remote sensing to air-based UAV remote sensing, changing the spatial dimension of observation. This lower-altitude platform maintains large-area coverage capability while providing higher spatial resolution imagery, enabling precise field-level drought monitoring that satellites cannot achieve.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Adaptability or versatility

If existing UAV drought monitoring methods are applied to field crops, then monitoring capability is provided, but the methods are not optimized for crop-specific growth stages and water requirements

Engineering Contradiction:
Improvemonitoring applicabilityVSAvoiddrought discrimination accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by establishing stage-specific chlorophyll content thresholds tailored to different maize growth stages (jointing, tasseling, flowering, maturity). Each growth stage has customized threshold ranges that reflect the crop's specific water requirements and physiological characteristics, enabling precise drought discrimination adapted to local crop needs.

Inventive Principle:
Principle #3Local quality

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 high-precision, rapid, and efficient drought monitoring and discrimination in large areas, with accurate classification of drought severity based on calibrated chlorophyll content thresholds, enhancing irrigation management.

Implementation Method 1

UAV-based low-altitude remote sensing technology can provide rapid and convenient services for information monitoring in large field areas

Methodology Applied
Scientific EffectRemote sensing:

Implementation Method 2

Remote sensing technology can better reflect changes in soil moisture and can quickly, efficiently, and non-destructively obtain drought information

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentUS12405259B2Rapid UAV-based monitoring and discrimination method for drought in summer maize based on chlorophyll content
Publication Date: 2025.09.02 CHINA INST OF WATER RESOURCES & HYDROPOWER RES
  • US12405259B2 patent drawing
  • US12405259B2 patent drawing
  • US12405259B2 patent drawing

AI summary

A rapid monitoring and discrimination method for drought conditions in summer maize based on chlorophyll content includes: 1) Obtaining multi-spectral imagery through UAV multi-payload low-altitude remote sensing technology and measuring chlorophyll content on the ground. Additionally, calculating vegetation indices including Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), and Renormalized Difference Vegetation Index (RENDVI). 2) Selecting vegetation indices and constructing regression equations with measured chlorophyll content during different growth stages. The regression equation with the highest correlation for each growth stage is chosen as the optimal model equation for that particular stage. 3) Using the optimal model equations to retrieve chlorophyll content for each period and determining thresholds for chlorophyll content across different drought levels through calibration. 4) Calculating the required vegetation indices from real-time multi-spectral imagery of the field under test, retrieving chlorophyll content, and comparing it with the established thresholds to assess the real-time drought level.