diff --git a/src/api/baseapi.cpp b/src/api/baseapi.cpp
index dccd7f2a..8127b5cd 100644
--- a/src/api/baseapi.cpp
+++ b/src/api/baseapi.cpp
@@ -955,6 +955,8 @@ const char *TessBaseAPI::GetDatapath() {
 }
 
 int TessBaseAPI::GetSourceYResolution() {
+  if (thresholder_ == nullptr)
+    return -1;
   return thresholder_->GetSourceYResolution();
 }