diff --git a/api/apps/document_app.py b/api/apps/document_app.py
index 0b3bfd6ba..b80d59b09 100644
--- a/api/apps/document_app.py
+++ b/api/apps/document_app.py
@@ -557,8 +557,8 @@ def get(doc_id):
 @login_required
 @validate_request("doc_id")
 def change_parser():
-    req = request.json
 
+    req = request.json
     if not DocumentService.accessible(req["doc_id"], current_user.id):
         return get_json_result(data=False, message="No authorization.", code=settings.RetCode.AUTHENTICATION_ERROR)
 
@@ -582,7 +582,7 @@ def change_parser():
                 settings.docStoreConn.delete({"doc_id": doc.id}, search.index_name(tenant_id), doc.kb_id)
 
     try:
-        if "pipeline_id" in req:
+        if "pipeline_id" in req and req["pipeline_id"] != "":
             if doc.pipeline_id == req["pipeline_id"]:
                 return get_json_result(data=True)
             DocumentService.update_by_id(doc.id, {"pipeline_id": req["pipeline_id"]})
diff --git a/deepdoc/parser/pdf_parser.py b/deepdoc/parser/pdf_parser.py
index ea3a87b14..c73b610ad 100644
--- a/deepdoc/parser/pdf_parser.py
+++ b/deepdoc/parser/pdf_parser.py
@@ -1274,12 +1274,16 @@ class VisionParser(RAGFlowPdfParser):
                 prompt=vision_llm_describe_prompt(page=pdf_page_num + 1),
                 callback=callback,
             )
+
             if kwargs.get("callback"):
                 kwargs["callback"](idx * 1.0 / len(self.page_images), f"Processed: {idx + 1}/{len(self.page_images)}")
 
             if text:
                 width, height = self.page_images[idx].size
-                all_docs.append((text, f"{pdf_page_num + 1} 0 {width / zoomin} 0 {height / zoomin}"))
+                all_docs.append((
+                    text,
+                    f"@@{pdf_page_num + 1}\t{0.0:.1f}\t{width / zoomin:.1f}\t{0.0:.1f}\t{height / zoomin:.1f}##"
+                ))
         return all_docs, []