diff --git a/examples/matching_to_many_images.rb b/examples/matching_to_many_images.rb
index 0fef936..b96b652 100644
--- a/examples/matching_to_many_images.rb
+++ b/examples/matching_to_many_images.rb
@@ -11,6 +11,6 @@ images = image_files.map{|f| IplImage.load f, CV_LOAD_IMAGE_GRAYSCALE}
 
 matchs = query.match_descriptors("SURF", "SURF", "FlannBased", images)
 
-match, count = matchs.max_by {|image, count| count}
+match_index, count = matchs.max_by {|image_index, count| count}
 
-puts "max match: #{image_files[images.index(match)]}"
+puts "max match: #{image_files[match_index]}"
diff --git a/ext/opencv/cvmat.cpp b/ext/opencv/cvmat.cpp
index 387b193..621725e 100644
--- a/ext/opencv/cvmat.cpp
+++ b/ext/opencv/cvmat.cpp
@@ -5336,7 +5336,7 @@ rb_match_shapes(int argc, VALUE *argv, VALUE self)
  *   match_descriptors(<i>detector_type, descriptor_type, matcher_type, images</i>) -> Hash
  *
  * Matching descriptors detected on one image to descriptors detected in image set.
- * Returns a Hash contains match count of each image.
+ * Returns a Hash contains match count of each image index.
  *
  * <i>detector_type</i> is a string, options: "SURF"
  * <i>descriptor_type</i> is a string, options: "SURF"
@@ -5377,7 +5377,7 @@ rb_match_descriptors(int argc, VALUE *argv, VALUE self)
 
   VALUE _matches = rb_hash_new();
   for (size_t i=0; i<matches.size(); i++) {
-    VALUE match = RARRAY_PTR(images)[matches[i].imgIdx];
+    VALUE match = INT2FIX(matches[i].imgIdx);
     VALUE count = rb_hash_aref(_matches, match);
     if (NIL_P(count)) {
       count = INT2FIX(1);