diff --git a/models/torch_utils.py b/models/torch_utils.py
index 8ad2a2e..b25ede9 100644
--- a/models/torch_utils.py
+++ b/models/torch_utils.py
@@ -64,12 +64,12 @@ def det_postprocess(data: Tuple[Tensor, Tensor, Tensor, Tensor]):
     iou_thres: float = 0.65
     num_dets, bboxes, scores, labels = data[0][0], data[1][0], data[2][
         0], data[3][0]
-    # check score negative
-    scores[scores < 0] = 1 + scores[scores < 0]
     nums = num_dets.item()
     if nums == 0:
         return bboxes.new_zeros((0, 4)), scores.new_zeros(
             (0, )), labels.new_zeros((0, ))
+    # check score negative
+    scores[scores < 0] = 1 + scores[scores < 0]
     # add nms
     idx = nms(bboxes, scores, iou_thres)
     bboxes, scores, labels = bboxes[idx], scores[idx], labels[idx]
diff --git a/models/utils.py b/models/utils.py
index db2da2d..5f22a3c 100644
--- a/models/utils.py
+++ b/models/utils.py
@@ -90,12 +90,12 @@ def det_postprocess(data: Tuple[ndarray, ndarray, ndarray, ndarray]):
     assert len(data) == 4
     iou_thres: float = 0.65
     num_dets, bboxes, scores, labels = (i[0] for i in data)
-    # check score negative
-    scores[scores < 0] = 1 + scores[scores < 0]
     nums = num_dets.item()
     if nums == 0:
         return np.empty((0, 4), dtype=np.float32), np.empty(
             (0, ), dtype=np.float32), np.empty((0, ), dtype=np.int32)
+    # check score negative
+    scores[scores < 0] = 1 + scores[scores < 0]
     # add nms
     idx = nms(bboxes, scores, iou_thres)
     bboxes, scores, labels = bboxes[idx], scores[idx], labels[idx]