diff --git a/sources/libcpp55iip_scan/sane_scan.cpp b/sources/libcpp55iip_scan/sane_scan.cpp

index 04896d6..5d17445 100644

--- a/sources/libcpp55iip_scan/sane_scan.cpp

+++ b/sources/libcpp55iip_scan/sane_scan.cpp

@@ -532,6 +532,7 @@ double iip_scan::gts_coord_to_sane(double x, double res) {

     switch(this->_coordinate_unit) {

         case SANE_UNIT_MM:

             return x * 10;

+        default:

         case SANE_UNIT_PIXEL:

             return x * 0.393701 * res;

     }