app.py

import gradio as gr
import torch
import numpy as np
from PIL import Image
import matplotlib.pyplot as plt
import io

from pathlib import Path
import os, shutil
from tqdm.auto import tqdm
import torchvision
from torch.utils.data import DataLoader
from torchvision.datasets import ImageFolder
from torchvision.transforms import transforms
import torch.optim as optim
from torchvision.models import resnet50, ResNet50_Weights
import urllib.request
import tarfile

# Transform
transform = transforms.Compose([
    transforms.Resize((224,224)),
    transforms.ToTensor()
])

# Dataset download
urllib.request.urlretrieve(
    "https://www.mydrive.ch/shares/38536/3830184030e49fe74747669442f0f282/download/420937484-1629951672/carpet.tar.xz",
    "carpet.tar.xz"
)

with tarfile.open('carpet.tar.xz') as f:
    f.extractall('.')

# Feature extractor class
class resnet_feature_extractor(torch.nn.Module):
    def __init__(self):
        super(resnet_feature_extractor, self).__init__()
        self.model = resnet50(weights=ResNet50_Weights.DEFAULT)
        self.model.eval()
        for param in self.model.parameters():
            param.requires_grad = False

        def hook(module, input, output):
            self.features.append(output)

        self.model.layer2[-1].register_forward_hook(hook)            
        self.model.layer3[-1].register_forward_hook(hook) 

    def forward(self, input):
        self.features = []
        with torch.no_grad():
            _ = self.model(input)

        self.avg = torch.nn.AvgPool2d(3, stride=1)
        fmap_size = self.features[0].shape[-2]
        self.resize = torch.nn.AdaptiveAvgPool2d(fmap_size)

        resized_maps = [self.resize(self.avg(fmap)) for fmap in self.features]
        patch = torch.cat(resized_maps, 1)
        patch = patch.reshape(patch.shape[1], -1).T
        return patch

# Initialize backbone
backbone = resnet_feature_extractor()

# Memory bank
memory_bank = []
folder_path = Path("carpet/train/good")
for pth in tqdm(folder_path.iterdir(), leave=False):
    with torch.no_grad():
        data = transform(Image.open(pth)).unsqueeze(0)
        features = backbone(data)
        memory_bank.append(features.cpu().detach())
memory_bank = torch.cat(memory_bank, dim=0)

# Threshold
y_score = []
for pth in tqdm(folder_path.iterdir(), leave=False):
    data = transform(Image.open(pth)).unsqueeze(0)
    with torch.no_grad():
        features = backbone(data)
    distances = torch.cdist(features, memory_bank, p=2.0)
    dist_score, _ = torch.min(distances, dim=1) 
    s_star = torch.max(dist_score)
    y_score.append(s_star.cpu().numpy())

best_threshold = np.mean(y_score) + 2 * np.std(y_score)


# Gradio Function

def detect_fault(uploaded_image):
    test_image = transform(uploaded_image).unsqueeze(0)

    with torch.no_grad():
        features = backbone(test_image)

    distances = torch.cdist(features, memory_bank, p=2.0)
    dist_score, _ = torch.min(distances, dim=1) 
    s_star = torch.max(dist_score)
    segm_map = dist_score.view(1, 1, 28, 28) 
    segm_map = torch.nn.functional.interpolate(
                segm_map,
                size=(224, 224),
                mode='bilinear'
            ).cpu().squeeze().numpy()

    y_score_image = s_star.cpu().numpy()
    y_pred_image = 1*(y_score_image >= best_threshold)
    class_label = ['Image Is OK','Image Is Not OK']

    # Plot results
    fig, axs = plt.subplots(1, 3, figsize=(15, 5))
    axs[0].imshow(test_image.squeeze().permute(1,2,0).cpu().numpy())
    axs[0].set_title("Original Image")
    axs[0].axis("off")

    axs[1].imshow(segm_map, cmap='jet')
    axs[1].set_title(f"Anomaly Score: {y_score_image / best_threshold:0.4f}\nPrediction: {class_label[y_pred_image]}")
    axs[1].axis("off")

    axs[2].imshow((segm_map > best_threshold*1.25), cmap='gray')
    axs[2].set_title("Fault Segmentation Map")
    axs[2].axis("off")

    buf = io.BytesIO()
    plt.savefig(buf, format="png")
    buf.seek(0)
    result_image = Image.open(buf)
    plt.close(fig)

    return result_image

# Launch Gradio App
demo = gr.Interface(
    fn=detect_fault,
    inputs=gr.Image(type="pil", label="Upload Image"),
    outputs=gr.Image(type="pil", label="Detection Result"),
    title="Fault Detection in Images",
    description="Upload an image and the model will detect if there are any faults and show the segmentation map."
)

if __name__ == "__main__":
    demo.launch()