average_distance.py

# returns distance (a float) if face detected in synthesized image, None otherwise
def distance_metric(y_pred, x, dlib_models):
    dist = None 

    face_detector, landmark_detector, face_embedder = dlib_models
    face_boxes = face_detector(y_pred, 1)

    if len(face_boxes) == 1:
        landmarks = landmark_detector(y_pred, face_boxes[0])
        embedding = face_embedder.compute_face_descriptor(y_pred, landmarks)
        dist = np.linalg.norm(np.array(embedding) - np.array(x))
        
    return dist