import cv2
import numpy as np
import os

# Paths (change these to your actual file paths)
image_path = "car.jpg"  # Original car image
mask_path = "car_mask.png"  # Segmented mask image
output_path = "car_transparent.png"  # Output image

# Load images
car_image = cv2.imread(image_path, cv2.IMREAD_UNCHANGED)  # Read original image
mask = cv2.imread(mask_path, cv2.IMREAD_GRAYSCALE)  # Read mask in grayscale

# Ensure both images are the same size
if car_image.shape[:2] != mask.shape[:2]:
    mask = cv2.resize(mask, (car_image.shape[1], car_image.shape[0]))

# Normalize mask to be binary (0 for background, 255 for car)
_, binary_mask = cv2.threshold(mask, 128, 255, cv2.THRESH_BINARY)

# Create an alpha channel where car is visible (255) and background is transparent (0)
alpha_channel = binary_mask.copy()

# Convert original image to RGBA (add alpha channel)
rgba_image = cv2.cvtColor(car_image, cv2.COLOR_BGR2BGRA)
rgba_image[:, :, 3] = alpha_channel  # Assign alpha channel

# Save the output as a transparent PNG
cv2.imwrite(output_path, rgba_image)

print(f"✅ Transparent image saved at: {output_path}")