diff --git a/rtengine/capturesharpening.cc b/rtengine/capturesharpening.cc
index 072935dc2..14e9b95e5 100644
--- a/rtengine/capturesharpening.cc
+++ b/rtengine/capturesharpening.cc
@@ -790,6 +790,10 @@ BENCHFUN
         }
     }
 
+    if (std::isnan(radius)) {
+        return;
+    }
+
     if (showMask) {
         array2D<float>& L = blue; // blue will be overridden anyway => we can use its buffer to store L
 #ifdef _OPENMP