rotttenfruits

Object Detection Model for Rotten Fruits

By Aiden Luo

Model Description

This is an object detection model that finds apples and oranges along with their rotten variants. The model is fine tuned from YOLOv11, which orignally uses COCO as its dataset. It is meant to detect rotten fruits on a conveyor belt when mass processing produce.

Training Data

Dataset

[https://www.kaggle.com/datasets/muhammad0subhan/fruit-and-vegetable-disease-healthy-vs-rotten]

Classes: 28

Images: 29,291

Data Collection

Dataset is a combination of other datasets containing fruit and vegetables, rotten and healthy, then manually valiadated and sorted.

Class Distribution and Annotations

I used only 4 of the 28 classes (Apple_Healthy, Orange_Healthy,Apple_Rotten, Orange_Rotten). Annotated 1000 images using Roboflow's SAM3 autolabel, and validating 1000 of them. Manually added 578 detections, and fixed about 30% of the annotations as they were false positives.

Augmentations

• Rotation
• Translate
• Horizontal flipping
• Mosaic

Training Procedure

• Framework Ultralytics
• Hardware NVIDIA Tesla T4
• Batch Size 64
• Epochs 100
• Patience 50

Metrics (Epoch 100)

Examples

Apple : Red and green apples with a simple background. <img src='simpleapple.png' width="400" height="400"> <img src='simplegreenapple.png' width="400" height="400">

Orange : Oranges with a simple background. <img src='manyoranges.png' width="400" height="400"> <img src='simpleorange.jpg' width="400" height="400">

RottenApple : Moldy apples or deformed/old apples with a simple background. <img src='moldyapple.png' width="400" height="400"> <img src='deformedapple.png' width="400" height="400">

RottenOrange : Moldy oranges or deformed oranges with a simple background. <img src='deformedorange.png' width="400" height="400"> <img src='moldyorange.png' width="400" height="400">

F1-Score

<img src='BoxF1_curve.png' alt="F1 Curve Graph" width="700" height="700">

Confusion Matrix

<img src='confusion_matrix_normalized.png' alt="Confusion Matrix Graph" width="700" height="700">

Train/Loss and Val/Loss Curves

<img src='results.png' alt="Training and Validation Loss Curve Graph" width="700" height="700">

Performance Analysis

My results show generally a very strong performance across the board, performing the best at all classes with a F1-score of 0.92 at a confidence level of 58%. It is good at both finding and identifying the object, however the confusion matrix does show some problems; the Orange class and background get mixed up fairly often despite a relatively strong diagonal shown in the matrix. There is also no signs of obvious over or underfitting shown in the class/val loss curves, they both steadily curve down. However, the model could likely still be improved with more training or more images, as the curves don't seem like they've completely plateaud yet.

Limatations and Biases

Failure Cases Struggles with the inside of fruits and human hands in background. <img src='failcase1.png' width="400" height="400"> <img src='failcase2.png' width="400" height="400">

Poor Peforming classes
Although they all have very high metrics, the Orange class likely performs the worst. It gets mixed up on the background the most, likely because the dataset contains quite a few images with orange backgrounds.

Data Biases/Contextual limitations Many images were blurry or low resolution, similarly some images contained logos or stock image words printed over the fruits. Many of the fruits were all very similar in species, there were fewer green apples and blood oranges in the dataset. The model significantly degrades when the background is not simple or matches the examples.

Innappropriate Use Cases This model is meant for conveyor belts, however anything that creates a non-static background such as human workers will mess with model accuracy.

Sample size limitations The entire model could benefit from at least thousands more images in each class, but they can be very similar images as I want the model to be sucessful on a conveyor belt and not much else. It's okay if it gets confused on human hands or can't detect the inside of a fruit as that usually won't happen on a conveyor belt.