Update app.py

app.py

@@ -2,7 +2,8 @@
 building-segmentation
 Proof of concept showing effectiveness of a fine tuned instance segmentation model for deteting buildings.
 """
-import os, json, cv2, random
+import os
+import cv2
 os.system("pip install 'git+https://github.com/facebookresearch/detectron2.git'")
 from transformers import DetrFeatureExtractor, DetrForSegmentation
 from PIL import Image