diff --git a/src/reflectionReconstruction/preprocessData/preprocessAScanBlockForReflection.cpp b/src/reflectionReconstruction/preprocessData/preprocessAScanBlockForReflection.cpp
index bbde6bb..b211741 100644
--- a/src/reflectionReconstruction/preprocessData/preprocessAScanBlockForReflection.cpp
+++ b/src/reflectionReconstruction/preprocessData/preprocessAScanBlockForReflection.cpp
@@ -187,7 +187,7 @@ namespace Recon {
                 Aurora::Matrix fh;
                 if (!preComputes.measuredCEUsed)
                 {
-                    fh = preComputes.matchedFilter.block(1, 0, nAScans-1);
+                    fh = preComputes.matchedFilter.block(1, 0, 0);
                 }
                 else{
                     fh = preComputes.matchedFilter(Aurora::$,blockedChannels[i]-1).toMatrix();