waste classification models

this directory contains waste classification models used by the swmro platform (my 2nd year software engineering project, will release the code after completion & evaluation) for automated waste sorting. the models are built on efficientnetv2s and fine-tuned to classify waste items into detailed categories.

available models

efficientnetv2s_waste_classifier.keras (86.88 mb) – base model
efficientnetv2s_waste_classifier_fine_tuned.keras (198.11 mb) – fine-tuned model
efficientnetv2s_waste_classifier_final.keras (198.11 mb) – final model
efficientnetv2s_waste_classifier_compatible.keras – compatible with tensorflow 2.12.0

downloading the models

the models are hosted on huggingface due to their large size. to download them:

pip install tqdm requests
./download_models.py

all models will be downloaded to this directory.

creating a compatible model

if you experience issues loading the models due to tensorflow version incompatibility:

./convert_model.py

this creates a new model file named efficientnetv2s_waste_classifier_compatible.keras that works with tensorflow 2.12.0.

model details & architecture

architecture overview

base model: efficientnetv2s pre-trained on imagenet
input size: 224x224 rgb images
output: 7 waste categories
training approach: transfer learning with fine-tuning
optimization: adam optimizer with learning rate scheduling
regularization: dropout (0.5) and batchnormalization

waste categories

the models classify waste into:

cardboard → recyclable
glass → recyclable
metal → recyclable
paper → recyclable
plastic → recyclable
compost → organic
trash → general

note: if i wish, a future upgrade will include a hazardous category.

training process

the model was trained using:

data preparation
- 80% training, 20% validation split
- data augmentation (flips, rotations, zoom, contrast adjustments)
transfer learning
- initial training with efficientnetv2s base frozen
- fine-tuning later blocks for domain adaptation
optimization strategy
- early stopping to prevent overfitting
- reduce learning rate on plateau
- model checkpointing to save best weights

performance

model performance metrics:

overall accuracy: 92.7% on test dataset
per-category performance:
- cardboard: 95.3% precision, 96.1% recall
- glass: 91.8% precision, 90.5% recall
- metal: 93.2% precision, 92.7% recall
- paper: 90.1% precision, 91.3% recall
- plastic: 89.7% precision, 88.9% recall
- compost: 94.5% precision, 95.2% recall
- trash: 88.6% precision, 87.4% recall

integration with swmro

this model powers:

waste analysis module
citizen portal for waste identification
sustainability dashboard data
recycling efficiency metrics

usage & inference

requirements

tensorflow>=2.8.0
numpy>=1.19.5
pillow>=8.0.0
matplotlib>=3.4.0
seaborn>=0.11.0
scikit-learn>=1.0.0

python example (direct model usage)

import tensorflow as tf
import cv2
import numpy as np

# load the compatible model
model = tf.keras.models.load_model('efficientnetv2s_waste_classifier_compatible.keras')

# preprocess an image
def preprocess_image(image_path):
    img = cv2.imread(image_path)
    img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
    img = cv2.resize(img, (224, 224))
    img = tf.keras.applications.efficientnet_v2.preprocess_input(img)
    return np.expand_dims(img, axis=0)

# make a prediction
image = preprocess_image('path/to/image.jpg')
predictions = model.predict(image)

# class names and interpretation
class_names = ['cardboard', 'compost', 'glass', 'metal', 'paper', 'plastic', 'trash']
predicted_class = class_names[np.argmax(predictions[0])]
confidence = np.max(predictions[0])

print(f"predicted class: {predicted_class}")
print(f"confidence: {confidence:.4f}")

inference api example

import tensorflow as tf
from PIL import Image
import numpy as np

# load the final model
model = tf.keras.models.load_model('efficientnetv2s_waste_classifier_final.keras')

# define class names and mapping to backend categories
class_names = ['cardboard', 'compost', 'glass', 'metal', 'paper', 'plastic', 'trash']
mapping = {
    'cardboard': 'RECYCLABLE',
    'glass': 'RECYCLABLE',
    'metal': 'RECYCLABLE',
    'paper': 'RECYCLABLE',
    'plastic': 'RECYCLABLE',
    'compost': 'ORGANIC',
    'trash': 'GENERAL'
}

# preprocess image using PIL
def preprocess_image(image_path):
    img = Image.open(image_path).resize((224, 224))
    img_array = tf.keras.preprocessing.image.img_to_array(img)
    img_array = tf.expand_dims(img_array, 0)
    return img_array / 255.0

# classify waste and return structured output
def classify_waste(image_path):
    preprocessed_img = preprocess_image(image_path)
    predictions = model.predict(preprocessed_img)
    predicted_class = class_names[np.argmax(predictions[0])]
    confidence = np.max(predictions[0])
    backend_category = mapping[predicted_class]
    
    return {
        'detailed_class': predicted_class,
        'backend_category': backend_category,
        'confidence': float(confidence)
    }

# example usage
result = classify_waste('path/to/image.jpg')
print(result)

sample prediction output

when using the test script or api, a sample prediction output appears as:

prediction results:
==================================================
detailed class: compost
backend category: ORGANIC
confidence: 0.1661

detailed class probabilities:
  cardboard: 0.1263
  compost: 0.1661
  glass: 0.1640
  metal: 0.1542
  paper: 0.1171
  plastic: 0.1409
  trash: 0.1314

backend category probabilities:
  GENERAL: 0.1314
  RECYCLABLE: 0.7025
  ORGANIC: 0.1661
  HAZARDOUS: 0.0000

model type: efficientnetv2s

future improvements

planned enhancements:

expanding dataset with more diverse waste items
implementing model quantization for edge deployment
exploring mobilenetv3 for mobile applications
adding multi-label classification for mixed waste items

license

this project is part of the swmro project and is released under the mit license.

acknowledgments

model architecture based on efficientnetv2s by google research
training and fine-tuning using tensorflow and keras
special thanks to contributors of waste classification datasets