diff --git a/python/examples/ocr/ocr_debugger_server.py b/python/examples/ocr/ocr_debugger_server.py
index dae74241ca60a5f501538ec3200f83b3806f0f69..4463fb22d128704b206c6e1f684a893ee40c50b2 100644
--- a/python/examples/ocr/ocr_debugger_server.py
+++ b/python/examples/ocr/ocr_debugger_server.py
@@ -82,7 +82,7 @@ class OCRService(WebService):
         for id, img in enumerate(img_list):
             norm_img = self.ocr_reader.resize_norm_img(img, max_wh_ratio)
             imgs[id] = norm_img
-        feed = {"image": imgs}
+        feed = {"image": imgs.copy()}
         fetch = ["ctc_greedy_decoder_0.tmp_0", "softmax_0.tmp_0"]
         return feed, fetch