diff --git a/include/aare/RawFile.hpp b/include/aare/RawFile.hpp
index a629315f..74e74c3a 100644
--- a/include/aare/RawFile.hpp
+++ b/include/aare/RawFile.hpp
@@ -125,7 +125,7 @@ class RawFile : public FileInterface {
     size_t n_modules() const;
 
     /**
-     * @brief number of ROIs defined
+     * @brief number of ROIs defined (always 1 for complete ROI)
      */
     size_t num_rois() const;
 
diff --git a/include/aare/utils/utility_functions.hpp b/include/aare/utils/utility_functions.hpp
index 7a399247..28d60d47 100644
--- a/include/aare/utils/utility_functions.hpp
+++ b/include/aare/utils/utility_functions.hpp
@@ -113,4 +113,19 @@ inline bool complete_ROI(const std::vector<ROI> &rois,
     }
 }
 
+inline bool complete_ROI(const ROIGeometry &roi,
+                         const DetectorGeometry &geometry) {
+    return roi.pixels_x() == geometry.pixels_x() &&
+           roi.pixels_y() == geometry.pixels_y();
+}
+
+inline bool complete_ROI(const std::vector<ROIGeometry> &rois,
+                         const DetectorGeometry &geometry) {
+    if (rois.empty() or rois.size() > 1) {
+        return false;
+    } else {
+        return complete_ROI(rois[0], geometry);
+    }
+}
+
 } // namespace aare
\ No newline at end of file
diff --git a/src/RawFile.cpp b/src/RawFile.cpp
index 72c95a46..1a8520c8 100644
--- a/src/RawFile.cpp
+++ b/src/RawFile.cpp
@@ -448,13 +448,7 @@ xy RawFile::geometry() const {
 
 size_t RawFile::n_modules() const { return m_geometry.n_modules(); };
 
-size_t RawFile::num_rois() const {
-    if (m_master.rois().has_value()) {
-        return m_master.rois()->size();
-    } else {
-        return 0;
-    }
-}
+size_t RawFile::num_rois() const { return m_ROI_geometries.size(); }
 
 const ROIGeometry &RawFile::roi_geometries(size_t roi_index) const {
     return m_ROI_geometries[roi_index];