diff --git a/libs/visualization/pil_utils.py b/libs/visualization/pil_utils.py
index e7665af..b5a0c0b 100644
--- a/libs/visualization/pil_utils.py
+++ b/libs/visualization/pil_utils.py
@@ -50,8 +50,7 @@ def draw_bbox(step, image, name='', image_height=1, image_width=1, bbox=None, la
 
     return source_img.save(FLAGS.train_dir + '/est_imgs/test_' + name + '_' +  str(step) +'.jpg', 'JPEG')
 
-def cat_id_to_cls_name(catId):
-    cls_name = np.array([  'background', 'person', 'bicycle', 'car', 'motorcycle', 'airplane',
+_CLS_NAMES = np.array(['background', 'person', 'bicycle', 'car', 'motorcycle', 'airplane',
                        'bus', 'train', 'truck', 'boat', 'traffic light', 'fire hydrant',
                        'stop sign', 'parking meter', 'bench', 'bird', 'cat', 'dog',
                        'horse', 'sheep', 'cow', 'elephant', 'bear', 'zebra', 'giraffe',
@@ -65,4 +64,7 @@ def cat_id_to_cls_name(catId):
                        'mouse', 'remote', 'keyboard', 'cell phone', 'microwave', 'oven',
                        'toaster', 'sink', 'refrigerator', 'book', 'clock', 'vase',
                        'scissors', 'teddy bear', 'hair drier', 'toothbrush'])
-    return cls_name[catId]
\ No newline at end of file
+
+def cat_id_to_cls_name(catId):
+    global _CLS_NAMES
+    return _CLS_NAMES[catId]