import cv2

def check_channels(image):
    channels = image.shape[2] if len(image.shape) == 3 else 1
    if channels == 1:
        image = cv2.cvtColor(image, cv2.COLOR_GRAY2BGR)
    elif channels > 3:
        image = image[:, :, :3]
    return image


def resize_image(img, max_length=768):
    height, width = img.shape[:2]
    max_dimension = max(height, width)

    if max_dimension > max_length:
        scale_factor = max_length / max_dimension
        new_width = int(round(width * scale_factor))
        new_height = int(round(height * scale_factor))
        new_size = (new_width, new_height)
        img = cv2.resize(img, new_size)
    height, width = img.shape[:2]
    img = cv2.resize(img, (width-(width % 64), height-(height % 64)))
    return img