def alpha_blend(input_image, segmentation_mask, alpha=0.5):
    """Alpha Blending utility to overlay RGB masks on RBG images
        :param input_image is a np.ndarray with 3 channels
        :param segmentation_mask is a np.ndarray with 3 channels
        :param alpha is a float value
    """
    # blended = np.zeros(input_image.size, dtype=np.float32)
    blended = input_image * alpha + segmentation_mask * (1 - alpha)
    return blended