v3.5: edge detect and image crop for dark background.

blues/idc.py

@@ -109,7 +109,7 @@ class IdcView(views.MethodView):
             save_img(raw_path, images[idx])
             return Response(data=info)
         else:
-            msg = "识别失败，建议使用深色背景\n识别结果：\n" + "\n".join(err_rec)
+            msg = "识别失败，建议使用深色背景"
             return Response(msg, info)