UV-A Fluorescence Detection for Latent Citrus Rot Sorting
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Solution Overview
Problem
Current manual sorting systems using UV light to detect rot in citrus fruits are inefficient, pose health risks to operators, and are costly due to high personnel costs and limitations in detecting latent infections, with no existing automatic systems capable of utilizing fluorescence for rot detection.
Innovation Solution
An automated system employing UV-A light to detect fluorescence from affected citrus fruits, utilizing two cameras positioned opposite each other to capture images from different angles, ensuring comprehensive surface coverage and eliminating 'dead spots, with an encoder controlling the expulsion of rotten fruits from the conveyor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual sorting operations are used to detect rot in citrus fruits, then the system can identify defective fruits, but the operation is not always effective due to the possibility that damage caused by rot is still not externally visible at the time of sorting
Solution Approach 1:
The system performs preliminary detection of latent rot infections before they become externally visible. By using UV light illumination to excite fluorescence from fungal metabolites in early-stage infections, the system identifies affected fruits before conventional visual inspection can detect them, enabling earlier separation and preventing spread to healthy fruits.
Solution Approach 2:
The system detects rot through fluorescence emission - a color change phenomenon. When UV light illuminates the fruit surface, areas with latent rot infections emit visible fluorescence due to fungal metabolites, creating a visual signal that distinguishes infected areas from healthy tissue before external symptoms appear.
2Measurement precision
If manual sorting operations are used, then operators can inspect fruits, but personnel costs are high and health risks are posed to operators
Solution Approach 1:
The system replaces manual mechanical inspection with an automated optical detection system. UV light sources illuminate the fruits and cameras capture fluorescence emissions, eliminating the need for human operators to physically handle and inspect each fruit, thereby reducing labor costs and health risks while maintaining or improving detection precision.
Solution Approach 2:
The system enables self-inspection of fruits through their own fluorescence properties. The fruits themselves reveal their infection status by emitting fluorescence when exposed to UV light, eliminating the need for external human judgment and making the detection process objective, consistent, and automated.
3Device complexity
If a single camera is used to capture fruit images, then the device complexity is reduced, but dead spots are created where rot may not be detected
Solution Approach 1:
The detection system is segmented into multiple camera units positioned at different locations. Each camera captures a specific portion of the fruit surface, and the combined data from multiple segments provides complete coverage. This segmentation eliminates dead spots where rot might be missed while distributing the complexity across modular components.
Solution Approach 2:
The system transitions from single-point inspection to multi-dimensional surface coverage by positioning cameras at different spatial locations around the fruit conveyor. This three-dimensional arrangement ensures that all surfaces of rotating or moving fruits are captured, eliminating blind spots while maintaining manageable device complexity through systematic positioning.
4Measurement precision
If UV light is used to detect latent rot, then fluorescence makes damage visible, but the system requires automatic separation capability to prevent spread
Solution Approach 1:
The system implements real-time feedback from detection to separation. Cameras continuously monitor fruit fluorescence, the control system processes images to identify infected fruits, and the expulsion mechanism responds immediately by separating detected defective fruits. This closed-loop feedback ensures rapid response that maintains high productivity while preventing spread.
Solution Approach 2:
The separation action is prepared in advance through continuous monitoring and real-time identification. By detecting latent rot early through fluorescence and immediately identifying affected fruits on the conveyor, the system prepares for separation before the fruits can be packaged or distributed, enabling prompt removal that maintains production speed while preventing contamination spread.
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 identifies and automatically separates rotten fruits without human intervention, reducing personnel costs and health risks, while ensuring high accuracy in detecting latent rot infections, thereby maintaining fruit quality and reducing economic losses.
Implementation Method 1
the illumination of these tissues with UV light shows their fluorescence, making damage which is still latent visible
Implementation Method 2
the condition of the citrus fruits is determined in accordance with the nature of the fluorescence observed thereon and captured by two cameras after being filtered
Data Source
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AI summary
The invention relates to system conceived and designed to identify pieces of fruit, especially citrus fruits, affected by any amount of rot and to determine the automatic expulsion of these pieces from the conveyor moving them through the installation. The system comprises illuminating the fruits with UV-A band light in a computer vision unit, and capturing images of the illuminated fruits by means of a camera to send them to a general control member in order to detect fluorescences associated to the rot effect. The identified fruit is automatically expelled from the conveyor in an expulsion unit, the position of the defective fruit being determined with the aid of an encoder associated to the conveyor. The general control member is a PC type computer, equipped with specific application software.