import numpy as np
import pydicom
import cv2

def load_dicom_image(path):
    ds = pydicom.dcmread(path)
    img = ds.pixel_array.astype(np.float32)
    return img

def resize_image(img, target_size=(224, 224)):
    return cv2.resize(img, target_size, interpolation=cv2.INTER_LINEAR)

def normalize_image(img):
    return img / 255.0

def to_3channel(img):
    return np.stack([img, img, img], axis=-1)

def preprocess_dicom(path):
    img = load_dicom_image(path)
    img = resize_image(img)
    img = normalize_image(img)
    img = to_3channel(img)
    img = np.expand_dims(img, axis=0)
    return img