app.py

import gradio as gr
import torch
import torch.nn as nn
import cv2
import numpy as np

# --------------------
# Model Definition
# --------------------
class FireCNN(nn.Module):
    def __init__(self, num_classes=3):
        super(FireCNN, self).__init__()

        self.features = nn.Sequential(
            nn.Conv2d(3, 16, 3, padding=1),
            nn.BatchNorm2d(16),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(16, 32, 3, padding=1),
            nn.BatchNorm2d(32),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(32, 64, 3, padding=1),
            nn.BatchNorm2d(64),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(64, 128, 3, padding=1),
            nn.BatchNorm2d(128),
            nn.ReLU(),
            nn.MaxPool2d(2),
        )

        self.classifier = nn.Sequential(
            nn.Flatten(),
            nn.Linear(128 * 8 * 8, 128),
            nn.ReLU(),
            nn.Dropout(0.3),
            nn.Linear(128, num_classes)
        )

    def forward(self, x):
        x = self.features(x)
        x = self.classifier(x)
        return x


# --------------------
# Load Model
# --------------------
checkpoint = torch.load("fire_model.pth", map_location="cpu")

model = FireCNN()
model.load_state_dict(checkpoint["model_state_dict"])
model.eval()

IMG_SIZE = checkpoint["img_size"]

# --------------------
# Prediction Function
# --------------------
def predict(image):
    img = cv2.resize(image, (IMG_SIZE, IMG_SIZE))
    img = img / 255.0
    img = np.transpose(img, (2, 0, 1))
    img = torch.tensor(img, dtype=torch.float32).unsqueeze(0)

    with torch.no_grad():
        outputs = model(img)
        probs = torch.softmax(outputs, dim=1).squeeze().numpy()

    return {
        "fire": float(probs[0]),
        "smoke": float(probs[1]),
        "non_fire": float(probs[2])
    }


# --------------------
# Gradio Interface
# --------------------
demo = gr.Interface(
    fn=predict,
    inputs=gr.Image(type="numpy"),
    outputs=gr.Label(num_top_classes=3),
    title="🔥 Fire / Smoke Detection",
    description="Upload an image to detect Fire, Smoke, or Non-Fire"
)

demo.launch()