main.py

from fastapi import FastAPI, File, UploadFile, Response
from fastapi.responses import FileResponse
from ultralytics import YOLO
import cv2
import numpy as np
from PIL import Image
import io
import os

app = FastAPI()
uploads_dir = 'uploads'

if not os.path.exists(uploads_dir):
    os.makedirs(uploads_dir)

# Load the YOLO model
yolo_model_path = 'best.pt'
yolo_model = YOLO(yolo_model_path)

@app.post("/detect_objects")
async def detect_objects(file: UploadFile = File(...)):
    if file.filename.lower().endswith(('.png', '.jpg', '.jpeg')):
        # Read the uploaded image
        contents = await file.read()
        nparr = np.frombuffer(contents, np.uint8)
        img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)

        # Perform object detection with YOLO
        results = yolo_model(img)
        
        # Initialize bounding box dimensions
        combined_xmin = float('inf')
        combined_ymin = float('inf')
        combined_xmax = float('-inf')
        combined_ymax = float('-inf')
        
        # Process YOLO detections
        for detection in results[0].boxes.xyxy.tolist():
            xmin, ymin, xmax, ymax = detection
            combined_xmin = min(combined_xmin, xmin)
            combined_ymin = min(combined_ymin, ymin)
            combined_xmax = max(combined_xmax, xmax)
            combined_ymax = max(combined_ymax, ymax)
        
        # Round bounding box values to integers
        combined_xmin = int(combined_xmin)
        combined_ymin = int(combined_ymin)
        combined_xmax = int(combined_xmax)
        combined_ymax = int(combined_ymax)

        # Crop and annotate the image
        annotated_img = results[0].plot()  # Get annotated image as a numpy array
        cropped_img = img[combined_ymin:combined_ymax, combined_xmin:combined_xmax]
        
        # Convert the annotated image to bytes for response
        annotated_pil_image = Image.fromarray(annotated_img)
        img_byte_arr = io.BytesIO()
        annotated_pil_image.save(img_byte_arr, format='PNG')
        img_byte_arr.seek(0)
        
        # Prepare metadata for the response
        metadata = {
            "X-Min": combined_xmin,
            "Y-Min": combined_ymin,
            "X-Max": combined_xmax,
            "Y-Max": combined_ymax
        }
        
        # Create the response
        response = Response(img_byte_arr.getvalue(), media_type="image/png")
        for key, value in metadata.items():
            response.headers[key] = str(value)
        
        return response
    return {"error": "Invalid file format"}