diff --git a/README.md b/README.md
index 4eb8e1049..3a7d1944a 100755
--- a/README.md
+++ b/README.md
@@ -23,7 +23,12 @@ $ cd ..
 $ python convert_weight.py
 $ python freeze_graph.py
 ```
-4. Then you will get some `.pb` files in the root path.,  and run the demo script
+4. If you want to get darknet-yolov3 [weights](https://pjreddie.com/darknet/yolo/) work in this project,run the following scripts to convert it.
+```bashrc
+$ python from_darknet_weights_to_ckpt.py # If you just want pb files, skip to the next line.
+$ python from_darknet_weights_to_pb.py
+```
+5. Then you will get some `.pb` files in the root path.,  and run the demo script
 ```bashrc
 $ python image_demo.py
 $ python video_demo.py # if use camera, set video_path = 0
diff --git a/core/dataset.py b/core/dataset.py
index 485e21e79..1df3fbd99 100644
--- a/core/dataset.py
+++ b/core/dataset.py
@@ -119,8 +119,8 @@ def random_crop(self, image, bboxes):
 
             crop_xmin = max(0, int(max_bbox[0] - random.uniform(0, max_l_trans)))
             crop_ymin = max(0, int(max_bbox[1] - random.uniform(0, max_u_trans)))
-            crop_xmax = max(w, int(max_bbox[2] + random.uniform(0, max_r_trans)))
-            crop_ymax = max(h, int(max_bbox[3] + random.uniform(0, max_d_trans)))
+            crop_xmax = min(w, int(max_bbox[2] + random.uniform(0, max_r_trans)))
+            crop_ymax = min(h, int(max_bbox[3] + random.uniform(0, max_d_trans)))
 
             image = image[crop_ymin : crop_ymax, crop_xmin : crop_xmax]