app.py

import gradio as gr
import torch
from PIL import Image, ImageDraw, ImageFont
from transformers import DetrImageProcessor, DetrForObjectDetection
from pathlib import Path
import transformers

# Global variables to cache models
current_model = None
current_processor = None
current_model_name = None

# Available models with better selection
available_models = {
    # DETR Models
    "DETR ResNet-50": "facebook/detr-resnet-50",
    "DETR ResNet-101": "facebook/detr-resnet-101",
    "DETR DC5": "facebook/detr-resnet-50-dc5",
    "DETR ResNet-50 Face Only": "esraakh/detr_fine_tune_face_detection_final"
}


def load_model(model_key):
    """Load model and processor based on selected model key"""
    global current_model, current_processor, current_model_name

    model_name = available_models[model_key]

    # Only load if it's a different model
    if current_model_name != model_name:
        print(f"Loading model: {model_name}")
        current_processor = DetrImageProcessor.from_pretrained(model_name)
        current_model = DetrForObjectDetection.from_pretrained(model_name)
        current_model_name = model_name
        print(f"Model loaded: {model_name}")
        print(f"Available labels: {list(current_model.config.id2label.values())}")

    return current_model, current_processor


# Load font
font_path = Path("assets/fonts/arial.ttf")
if not font_path.exists():
    print(f"Font file {font_path} not found. Using default font.")
    font = ImageFont.load_default()
else:
    font = ImageFont.truetype(str(font_path), size=8)  # Reduced font size

# Set up translations for the app
translations = {
    "English": {
        "title": "## Enhanced Object Detection App\nUpload an image to detect objects using various DETR models.",
        "input_label": "Input Image",
        "output_label": "Detected Objects",
        "dropdown_label": "Label Language",
        "dropdown_detection_model_label": "Detection Model",
        "threshold_label": "Detection Threshold",
        "button": "Detect Objects",
        "info_label": "Detection Info",
        "model_fast": "General Objects (fast)",
        "model_precision": "General Objects (high precision)",
        "model_small": "Small Objects/Details (slow)",
        "model_faces": "Face Detection (people only)"
    },
    "Spanish": {
        "title": "## Aplicación Mejorada de Detección de Objetos\nSube una imagen para detectar objetos usando varios modelos DETR.",
        "input_label": "Imagen de entrada",
        "output_label": "Objetos detectados",
        "dropdown_label": "Idioma de las etiquetas",
        "dropdown_detection_model_label": "Modelo de detección",
        "threshold_label": "Umbral de detección",
        "button": "Detectar objetos",
        "info_label": "Información de detección",
        "model_fast": "Objetos generales (rápido)",
        "model_precision": "Objetos generales (precisión alta)",
        "model_small": "Objetos pequeños/detalles (lento)",
        "model_faces": "Detección de caras (solo personas)"
    },
    "French": {
        "title": "## Application Améliorée de Détection d'Objets\nTéléchargez une image pour détecter des objets avec divers modèles DETR.",
        "input_label": "Image d'entrée",
        "output_label": "Objets détectés",
        "dropdown_label": "Langue des étiquettes",
        "dropdown_detection_model_label": "Modèle de détection",
        "threshold_label": "Seuil de détection",
        "button": "Détecter les objets",
        "info_label": "Information de détection",
        "model_fast": "Objets généraux (rapide)",
        "model_precision": "Objets généraux (haute précision)",
        "model_small": "Petits objets/détails (lent)",
        "model_faces": "Détection de visages (personnes uniquement)"
    }
}


def t(language, key):
    return translations.get(language, translations["English"]).get(key, key)


def get_translated_model_choices(language):
    """Get model choices translated to the selected language"""
    model_mapping = {
        "DETR ResNet-50": "model_fast",
        "DETR ResNet-101": "model_precision",
        "DETR DC5": "model_small",
        "DETR ResNet-50 Face Only": "model_faces"
    }

    translated_choices = []
    for model_key in available_models.keys():
        if model_key in model_mapping:
            translation_key = model_mapping[model_key]
            translated_name = t(language, translation_key)
        else:
            translated_name = model_key  # Fallback to original name
        translated_choices.append(translated_name)

    return translated_choices


def get_model_key_from_translation(translated_name, language):
    """Get the original model key from translated name"""
    model_mapping = {
        "DETR ResNet-50": "model_fast",
        "DETR ResNet-101": "model_precision",
        "DETR DC5": "model_small",
        "DETR ResNet-50 Face Only": "model_faces"
    }

    # Reverse lookup
    for model_key, translation_key in model_mapping.items():
        if t(language, translation_key) == translated_name:
            return model_key

    # If not found, try direct match
    if translated_name in available_models:
        return translated_name

    # Default fallback
    return "DETR ResNet-50"


def get_helsinki_model(language_label):
    """Returns the Helsinki-NLP model name for translating from English to the selected language."""
    lang_map = {
        "Spanish": "es",
        "French": "fr",
        "English": "en"
    }
    target = lang_map.get(language_label)
    if not target or target == "en":
        return None
    return f"Helsinki-NLP/opus-mt-en-{target}"


# add cache for translations
translation_cache = {}


def translate_label(language_label, label):
    """Translates the given label to the target language."""
    # Check cache first
    cache_key = f"{language_label}_{label}"
    if cache_key in translation_cache:
        return translation_cache[cache_key]

    model_name = get_helsinki_model(language_label)
    if not model_name:
        return label

    try:
        translator = transformers.pipeline("translation", model=model_name)
        result = translator(label, max_length=40)
        translated = result[0]['translation_text']
        # Cache the result
        translation_cache[cache_key] = translated
        return translated
    except Exception as e:
        print(f"Translation error (429 or other): {e}")
        return label  # Return original if translation fails


def detect_objects(image, language_selector, translated_model_selector, threshold):
    """Enhanced object detection with adjustable threshold and better info"""
    # Get the actual model key from the translated name
    model_selector = get_model_key_from_translation(translated_model_selector, language_selector)

    print(f"Processing image. Language: {language_selector}, Model: {model_selector}, Threshold: {threshold}")

    # Load the selected model
    model, processor = load_model(model_selector)

    # Process the image
    inputs = processor(images=image, return_tensors="pt")
    outputs = model(**inputs)

    # Convert model output to usable detection results with custom threshold
    target_sizes = torch.tensor([image.size[::-1]])
    results = processor.post_process_object_detection(
        outputs, threshold=threshold, target_sizes=target_sizes
    )[0]

    # Create a copy of the image for drawing
    image_with_boxes = image.copy()
    draw = ImageDraw.Draw(image_with_boxes)

    # Detection info
    detection_info = f"Detected {len(results['scores'])} objects with threshold {threshold}\n"
    detection_info += f"Model: {translated_model_selector} ({model_selector})\n\n"

    # Colors for different confidence levels
    colors = {
        'high': 'red',  # > 0.8
        'medium': 'orange',  # 0.5-0.8
        'low': 'yellow'  # < 0.5
    }

    detected_objects = []

    for score, label, box in zip(results["scores"], results["labels"], results["boxes"]):
        confidence = score.item()
        box = [round(x, 2) for x in box.tolist()]

        # Choose color based on confidence
        if confidence > 0.8:
            color = colors['high']
        elif confidence > 0.5:
            color = colors['medium']
        else:
            color = colors['low']

        # Draw bounding box
        draw.rectangle(box, outline=color, width=3)

        # Prepare label text
        label_text = model.config.id2label[label.item()]
        translated_label = translate_label(language_selector, label_text)
        display_text = f"{translated_label}: {round(confidence, 3)}"

        # Store detection info
        detected_objects.append({
            'label': label_text,
            'translated': translated_label,
            'confidence': confidence,
            'box': box
        })

        # Calculate text position and size
        try:

            image_width = image.size[0]
            # Calculate the font size for drawing labels, ensuring it scales with image width but is never smaller than 50 pixels.
            font_size = max(image_width // 40, 12)  # Adjust font size based on image width
            font = ImageFont.truetype(str(font_path), size=font_size)

            text_bbox = draw.textbbox((0, 0), display_text, font=font)
            text_width = text_bbox[2] - text_bbox[0]
            text_height = text_bbox[3] - text_bbox[1]
        except:
            # Fallback for older PIL versions
            text_bbox = draw.textbbox((0, 0), display_text, font=font)
            text_width = text_bbox[2] - text_bbox[0]
            text_height = text_bbox[3] - text_bbox[1]


        # Draw text background
        text_bg = [
            box[0], box[1] - text_height - 4,
                    box[0] + text_width + 4, box[1]
        ]
        draw.rectangle(text_bg, fill="black")
        draw.text((box[0] + 2, box[1] - text_height - 2), display_text, fill="white", font=font)

    # Create detailed detection info
    if detected_objects:
        detection_info += "Objects found:\n"
        for obj in sorted(detected_objects, key=lambda x: x['confidence'], reverse=True):
            detection_info += f"- {obj['translated']} ({obj['label']}): {obj['confidence']:.3f}\n"
    else:
        detection_info += "No objects detected. Try lowering the threshold."

    return image_with_boxes, detection_info


def build_app():
    with gr.Blocks(theme=gr.themes.Soft()) as app:
        with gr.Row():
            title = gr.Markdown(t("English", "title"))

        with gr.Row():
            with gr.Column(scale=1):
                language_selector = gr.Dropdown(
                    choices=["English", "Spanish", "French"],
                    value="English",
                    label=t("English", "dropdown_label")
                )
            with gr.Column(scale=1):
                model_selector = gr.Dropdown(
                    choices=get_translated_model_choices("English"),
                    value=t("English", "model_fast"),  # Default to translated "fast" option
                    label=t("English", "dropdown_detection_model_label")
                )
            with gr.Column(scale=1):
                threshold_slider = gr.Slider(
                    minimum=0.1,
                    maximum=0.95,
                    value=0.5,  # Lowered default threshold
                    step=0.05,
                    label=t("English", "threshold_label")
                )

        with gr.Row():
            with gr.Column(scale=1):
                input_image = gr.Image(type="pil", label=t("English", "input_label"))
                button = gr.Button(t("English", "button"), variant="primary")
            with gr.Column(scale=1):
                output_image = gr.Image(label=t("English", "output_label"))
                detection_info = gr.Textbox(
                    label=t("English", "info_label"),
                    lines=10,
                    max_lines=15
                )

        # Function to update interface when language changes
        def update_interface(selected_language):
            translated_choices = get_translated_model_choices(selected_language)
            default_model = t(selected_language, "model_fast")

            return [
                gr.update(value=t(selected_language, "title")),
                gr.update(label=t(selected_language, "dropdown_label")),
                gr.update(
                    choices=translated_choices,
                    value=default_model,
                    label=t(selected_language, "dropdown_detection_model_label")
                ),
                gr.update(label=t(selected_language, "threshold_label")),
                gr.update(label=t(selected_language, "input_label")),
                gr.update(value=t(selected_language, "button")),
                gr.update(label=t(selected_language, "output_label")),
                gr.update(label=t(selected_language, "info_label"))
            ]

        # Connect language change event
        language_selector.change(
            fn=update_interface,
            inputs=language_selector,
            outputs=[title, language_selector, model_selector, threshold_slider,
                     input_image, button, output_image, detection_info],
            queue=False
        )

        # Connect detection button click event
        button.click(
            fn=detect_objects,
            inputs=[input_image, language_selector, model_selector, threshold_slider],
            outputs=[output_image, detection_info]
        )

    return app


# Initialize with default model
load_model("DETR ResNet-50")

# Launch the application
if __name__ == "__main__":
    app = build_app()
    app.launch()