---
license: mit
tags:
  - image-classification
  - pytorch
  - resnet18
  - butterflies
---

# ButterflyID_5class

**ButterflyID_5class** is an image classification model that identifies 5 butterfly species commonly observed in Missouri: Black Swallowtail, Common Buckeye, Eastern Tiger Swallowtail, Red-Spotted Purple, and Small White. Built with PyTorch using transfer learning on a fine-tuned ResNet18 backbone.

This is a v1 release — the species list is intentionally limited for now and is planned to expand over time. These species are not exclusive to Missouri; the dataset was simply built around locally available observations.

## Performance

Dataset split: 177 train / 35 val / 44 test images across 5 classes.

- **Best validation accuracy:** 94.29%
- **Final test accuracy:** 90.91%

**Per-class test accuracy:**

| Species | Accuracy |
|---|---|
| Common Buckeye | 100.00% (9/9) |
| Red-Spotted Purple | 100.00% (9/9) |
| Small White | 100.00% (9/9) |
| Eastern Tiger Swallowtail | 88.89% (8/9) |
| Black Swallowtail | 62.50% (5/8) |

Black Swallowtail is the model's weakest class, likely due to visual similarity with Eastern Tiger Swallowtail (both swallowtail species with overlapping wing shape/pattern features). Test set sizes are small (8-9 images per class), so individual misclassifications have a large effect on the reported percentage.

## Data

Training images were sourced from [iNaturalist](https://www.inaturalist.org/). Full data attribution and licensing details are available in ATTRIBUTIONS.md in the project repo.

## Usage

This checkpoint bundles both the trained model weights and the class name list together:

```python
import torch
from torchvision import models
import torch.nn as nn

checkpoint = torch.load("butterfly_model.pt", map_location="cpu")
class_names = checkpoint["class_names"]

model = models.resnet18(weights=None)
model.fc = nn.Linear(model.fc.in_features, len(class_names))
model.load_state_dict(checkpoint["model_state_dict"])
model.eval()
```

## Project

Part of the full-stack [ButterflyID project](https://github.com/devbyjen388/ButterflyID) (FastAPI backend + web frontend).