app.py

import torch 
import torchvision 
from torchvision.models.detection import FasterRCNN_ResNet50_FPN_Weights 
from PIL import Image 
import numpy as np 
import matplotlib.pyplot as plt 
import gradio as gr 
import os 
import sys
 
# Load the pre-trained model once 
model = torchvision.models.detection.fasterrcnn_resnet50_fpn(weights=FasterRCNN_ResNet50_FPN_Weights.DEFAULT) 
model.eval() 
 
# COCO class names 
COCO_INSTANCE_CATEGORY_NAMES = [ 
    '__background__', 'person', 'bicycle', 'car', 'motorcycle', 'airplane', 'bus', 
    'train', 'truck', 'boat', 'traffic light', 'fire hydrant', 'N/A', 'stop sign', 
    'parking meter', 'bench', 'bird', 'cat', 'dog', 'horse', 'sheep', 'cow', 
    'elephant', 'bear', 'zebra', 'giraffe', 'N/A', 'backpack', 'umbrella', 'N/A', 'N/A', 
    'handbag', 'tie', 'suitcase', 'frisbee', 'skis', 'snowboard', 'sports ball', 
    'kite', 'baseball bat', 'baseball glove', 'skateboard', 'surfboard', 'tennis racket', 
    'bottle', 'N/A', 'wine glass', 'cup', 'fork', 'knife', 'spoon', 'bowl', 
    'banana', 'apple', 'sandwich', 'orange', 'broccoli', 'carrot', 'hot dog', 'pizza', 
    'donut', 'cake', 'chair', 'couch', 'potted plant', 'bed', 'N/A', 'dining table', 
    'N/A', 'N/A', 'toilet', 'N/A', 'tv', 'laptop', 'mouse', 'remote', 'keyboard', 'cell phone', 
    'microwave', 'oven', 'toaster', 'sink', 'refrigerator', 'N/A', 'book', 
    'clock', 'vase', 'scissors', 'teddy bear', 'hair drier', 'toothbrush' 
] 

# Gradio-compatible detection function 
def detect_objects(image, threshold=0.5): 
    if image is None:
        print("Image is None, returning empty output", file=sys.stderr)
        # Create a blank image as output
        blank_img = Image.new('RGB', (400, 400), color='white')
        plt.figure(figsize=(10, 10))
        plt.imshow(blank_img)
        plt.text(0.5, 0.5, "No image provided", 
                 horizontalalignment='center', verticalalignment='center',
                 transform=plt.gca().transAxes, fontsize=20)
        plt.axis('off')
        output_path = "blank_output.png"
        plt.savefig(output_path)
        plt.close()
        return output_path
        
    try:
        print(f"Processing image of type {type(image)} and threshold {threshold}", file=sys.stderr)
        # Make sure threshold is a valid number
        if threshold is None:
            threshold = 0.5
            print("Threshold was None, using default 0.5", file=sys.stderr)
        
        # Convert threshold to float if it's not already
        threshold = float(threshold)
        
        transform = FasterRCNN_ResNet50_FPN_Weights.DEFAULT.transforms() 
        image_tensor = transform(image).unsqueeze(0) 
     
        with torch.no_grad(): 
            prediction = model(image_tensor)[0] 
     
        boxes = prediction['boxes'].cpu().numpy() 
        labels = prediction['labels'].cpu().numpy() 
        scores = prediction['scores'].cpu().numpy() 
     
        image_np = np.array(image) 
        plt.figure(figsize=(10, 10)) 
        plt.imshow(image_np) 
        ax = plt.gca() 
     
        for box, label, score in zip(boxes, labels, scores): 
            # Explicit debug prints to trace the comparison issue
            print(f"Score: {score}, Threshold: {threshold}, Type: {type(score)}/{type(threshold)}", file=sys.stderr)
            
            if score >= threshold: 
                x1, y1, x2, y2 = box 
                ax.add_patch(plt.Rectangle((x1, y1), x2 - x1, y2 - y1, 
                             fill=False, color='red', linewidth=2)) 
                class_name = COCO_INSTANCE_CATEGORY_NAMES[label] 
                ax.text(x1, y1, f'{class_name}: {score:.2f}', bbox=dict(facecolor='yellow', alpha=0.5), 
                        fontsize=12, color='black') 
     
        plt.axis('off') 
        plt.tight_layout() 
         
        # Save the figure to return 
        output_path = "output.png"
        plt.savefig(output_path) 
        plt.close() 
        return output_path
    except Exception as e:
        print(f"Error in detect_objects: {e}", file=sys.stderr)
        import traceback
        traceback.print_exc(file=sys.stderr)
        
        # Create an error image
        error_img = Image.new('RGB', (400, 400), color='white')
        plt.figure(figsize=(10, 10))
        plt.imshow(error_img)
        plt.text(0.5, 0.5, f"Error: {str(e)}", 
                 horizontalalignment='center', verticalalignment='center',
                 transform=plt.gca().transAxes, fontsize=12, wrap=True)
        plt.axis('off')
        error_path = "error_output.png"
        plt.savefig(error_path)
        plt.close()
        return error_path

# Create direct file paths for examples
# These exact filenames match what's visible in your repository
examples = [
    os.path.join("/home/user/app", "TEST_IMG_1.jpg"),
    os.path.join("/home/user/app", "TEST_IMG_2.JPG"),
    os.path.join("/home/user/app", "TEST_IMG_3.jpg"),
    os.path.join("/home/user/app", "TEST_IMG_4.jpg")
]

# Create Gradio interface
# Important: For Gradio examples, we need to create a list of lists
example_list = [[path] for path in examples if os.path.exists(path)]

print(f"Found {len(example_list)} valid examples: {example_list}", file=sys.stderr)

# Create Gradio interface with a simplified approach
interface = gr.Interface( 
    fn=detect_objects, 
    inputs=[
        gr.Image(type="pil", label="Input Image"),
        gr.Slider(minimum=0.0, maximum=1.0, value=0.5, step=0.05, label="Confidence Threshold")
    ],
    outputs=gr.Image(type="filepath", label="Detected Objects"),
    title="Faster R-CNN Object Detection",
    description="Upload an image to detect objects using a pretrained Faster R-CNN model.",
    examples=example_list,
    cache_examples=False  # Disable caching to avoid potential issues
)

# Launch with specific configuration for Hugging Face
if __name__ == "__main__":
    # Launch with debug mode enabled
    interface.launch(debug=True)