turn masked_frame into 2d mask

app.py

@@ -135,6 +135,8 @@ def track_and_mask(vid, masked_frame, original_list, mask_list, in_fps, dt_strin
     x, y, w, h = getBoundaries(masked_frame)
     f = 0
     
+    #turn 3d mask into 2d mask
+    masked_frame = cv2.cvtColor(masked_frame, cv2.COLOR_BGR2GRAY)
     #add first mask frame of the video by default
     mask_list.append(masked_frame)
     video_capture = cv2.VideoCapture()