diff --git a/src/cnn_face_detection.cc b/src/cnn_face_detection.cc
index 16f9d66..83ea66f 100644
--- a/src/cnn_face_detection.cc
+++ b/src/cnn_face_detection.cc
@@ -51,7 +51,7 @@ PHP_METHOD(CnnFaceDetection, detect)
 {
 	char *img_path;
 	size_t img_path_len;
-	long upsample_num = 1;
+	long upsample_num = 0;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|l", &img_path, &img_path_len, &upsample_num) == FAILURE){
 		zend_throw_exception_ex(zend_ce_exception, 0 TSRMLS_CC, "Unable to parse detect arguments");
diff --git a/src/face_detection.cc b/src/face_detection.cc
index 3a2563b..3d2bd17 100644
--- a/src/face_detection.cc
+++ b/src/face_detection.cc
@@ -2,6 +2,7 @@
 #include "../php_pdlib.h"
 #include "face_detection.h"
 
+#include <zend_exceptions.h>
 #include <dlib/image_processing/frontal_face_detector.h>
 #include <dlib/gui_widgets.h>
 #include <dlib/image_io.h>
@@ -14,26 +15,37 @@ PHP_FUNCTION(dlib_face_detection)
 {
     char  *img_path;
     size_t  img_path_len;
+    long upsample_num = 0;
 
-    if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &img_path, &img_path_len) == FAILURE) {
+    if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|l", &img_path, &img_path_len, &upsample_num) == FAILURE) {
+        zend_throw_exception_ex(zend_ce_exception, 0 TSRMLS_CC, "Unable to parse dlib_face_detection arguments");
         RETURN_FALSE;
     }
     try {
         frontal_face_detector detector = get_frontal_face_detector();
 
+        pyramid_down<2> pyr;
         array2d<unsigned char> img;
         load_image(img, img_path);
 
+        unsigned int levels = upsample_num;
+        while (levels > 0) {
+            levels--;
+            pyramid_up(img, pyr);
+        }
+
         array_init(return_value);
 
         std::vector<rectangle> dets = detector(img);
         for (unsigned long i = 0; i < dets.size(); ++i) {
+            rectangle rect = pyr.rect_down(dets[i], upsample_num);
+
             zval rect_arr;
             array_init(&rect_arr);
-            add_assoc_long(&rect_arr, "left", dets[i].left());
-            add_assoc_long(&rect_arr, "top", dets[i].top());
-            add_assoc_long(&rect_arr, "right", dets[i].right());
-            add_assoc_long(&rect_arr, "bottom", dets[i].bottom());
+            add_assoc_long(&rect_arr, "left", rect.left());
+            add_assoc_long(&rect_arr, "top", rect.top());
+            add_assoc_long(&rect_arr, "right", rect.right());
+            add_assoc_long(&rect_arr, "bottom", rect.bottom());
             // Add this assoc array to returned array
             //
             add_next_index_zval(return_value, &rect_arr);
diff --git a/tests/dlib_face_detection.phpt b/tests/dlib_face_detection.phpt
index 8057bf4..75fb99f 100644
--- a/tests/dlib_face_detection.phpt
+++ b/tests/dlib_face_detection.phpt
@@ -4,15 +4,25 @@ Frontal face detection.
 <?php if (!extension_loaded("pdlib") print "skip"; ?>
 --FILE--
 <?php
-printf("Detection\n");
+printf("Simple detection\n");
 $detected_faces = dlib_face_detection(__DIR__ . "/lenna.jpg");
 printf("Faces found = %d\n", count($detected_faces));
 foreach($detected_faces as $index => $detected_face) {
   printf("Face[%d] in bounding box (left=%d, top=%d, right=%d, bottom=%d)\n", $index,
     $detected_face["left"], $detected_face["top"], $detected_face["right"], $detected_face["bottom"]);
 }
+printf("Detection with upsampling\n");
+$detected_faces = dlib_face_detection(__DIR__ . "/lenna.jpg", 1);
+printf("Faces found = %d\n", count($detected_faces));
+foreach($detected_faces as $index => $detected_face) {
+  printf("Face[%d] in bounding box (left=%d, top=%d, right=%d, bottom=%d)\n", $index,
+    $detected_face["left"], $detected_face["top"], $detected_face["right"], $detected_face["bottom"]);
+}
 ?>
 --EXPECT--
-Detection
+Simple detection
 Faces found = 1
-Face[0] in bounding box (left=214, top=194, right=393, bottom=373)
\ No newline at end of file
+Face[0] in bounding box (left=214, top=194, right=393, bottom=373)
+Detection with upsampling
+Faces found = 1
+Face[0] in bounding box (left=201, top=180, right=386, bottom=366)
\ No newline at end of file