Leaf Chlorophyll Estimation Using Camera Exposure Data

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Solution Overview

Problem

Existing methods for estimating chlorophyll content in plant leaves, such as the SPAD-502Plus and smartphone-based solutions, are either expensive or require significant processing power, limiting their accessibility and versatility.

Innovation Solution

A method using a mobile computing device with a digital camera and a removably attached peripheral light source, capturing images with and without a leaf, and estimating chlorophyll content based on exposure data like exposure time, F-number, and ISO values, reducing processing power requirements and increasing device versatility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a dedicated device like SPAD-502Plus is used for measuring chlorophyll content, then measurement precision is improved, but device cost increases significantly

Engineering Contradiction:

Improvechlorophyll content measurement precisionVSAvoiddevice cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a digital camera to capture images of the leaf, creating a visual copy that can be analyzed to estimate chlorophyll content. This replaces the need for specialized optical sensors while maintaining measurement capability through image processing and color analysis.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The invention employs inexpensive components such as a standard digital camera, LED light source, and basic processing unit instead of expensive dedicated sensors. These affordable components achieve sufficient measurement precision for practical agricultural applications.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If smartphone-based solutions with LED and light guide are used, then device cost is reduced, but processing power requirements increase

Engineering Contradiction:

Improvedevice costVSAvoidprocessing power

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The patent removes the light guide component from the system, directly attaching the LED to the digital camera housing. This extraction simplifies the optical path and reduces the computational complexity required for image processing, thereby lowering processing power requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a light guide to direct light from the LED through the leaf to the sensor, the patent inverts the approach by placing the LED outside the camera housing to illuminate the leaf directly, with the camera capturing the transmitted light. This inversion eliminates the need for complex light guiding and reduces processing demands.

Inventive Principle:

Principle #13The other way round (Inversion)

3Use of energy by moving object

If a light guide is included in the device design, then light transmission efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvelight transmission efficiencyVSAvoiddevice complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent extracts and removes the light guide component entirely from the device design. The LED is positioned outside the camera housing to illuminate the leaf directly, eliminating the need for light guiding structures and significantly reducing device complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the LED light source with the digital camera housing, integrating the illumination function into the camera structure itself. This consolidation eliminates separate light guiding components and simplifies the overall device architecture.

Inventive Principle:

Principle #5Merging (Combining)

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 method provides a cost-effective, precise estimation of chlorophyll content using less powerful devices, such as low-end smartphones, with reduced processing power needs and improved versatility due to the external light source and absence of a light guide.

Implementation Method 1

SPAD-502Plus determines the relative amount of chlorophyll present by measuring the absorbance of the leaf in two wavelength regions

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

one silicone photodiode

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11885683B2Method for estimating chlorophyll content of a leaf

Publication Date: 2024.01.30 YARA INTERNATIONAL ASA

AI summary

A method of estimating chlorophyll content of a leaf including providing a device wherein the device includes a mobile computing device with a digital camera; and a peripheral removably attached to the mobile computing device, the peripheral including a light source aligned with the digital camera, wherein the peripheral provides for a space between the light source and the digital camera; capturing by the digital camera a first image of the light source turned on without the leaf interposed between the digital camera and the light source; retrieving exposure data of the first image; capturing by the digital camera a second image with the leaf interposed between the digital camera and the turned on light source; retrieving exposure data of the second image; and using a processor, estimating the chlorophyll content of the leaf based on the retrieved exposure data of the first and second images.