diff --git a/opencv/cvaux.go b/opencv/cvaux.go
index d9f3eba..5b9ec55 100644
--- a/opencv/cvaux.go
+++ b/opencv/cvaux.go
@@ -63,7 +63,7 @@ func LoadHaarClassifierCascade(haar string) *HaarCascade {
 
 func (this *HaarCascade) DetectObjects(image *IplImage) []*Rect {
 	storage := C.cvCreateMemStorage(0)
-	seq := C.cvHaarDetectObjects(unsafe.Pointer(image), this.cascade, storage, 1.1, 3, 0, C.cvSize(0, 0), C.cvSize(0, 0))
+	seq := C.cvHaarDetectObjects(unsafe.Pointer(image), this.cascade, storage, 1.1, 3, C.CV_HAAR_DO_CANNY_PRUNING, C.cvSize(0, 0), C.cvSize(0, 0))
 	var faces []*Rect
 	for i := 0; i < (int)(seq.total); i++ {
 		rect := (*Rect)((*_Ctype_CvRect)(unsafe.Pointer(C.cvGetSeqElem(seq, C.int(i)))))
diff --git a/samples/face_detect.go b/samples/face_detect.go
index afd948c..d0c7e69 100644
--- a/samples/face_detect.go
+++ b/samples/face_detect.go
@@ -14,7 +14,6 @@ func main() {
 	faces := cascade.DetectObjects(image)
 
 	for _, value := range faces {
-		opencv.Circle(image, opencv.Point{value.X(), value.Y()}, 2, opencv.ScalarAll(255.0), 1, 1, 0)
 		opencv.Rectangle(image,
 			opencv.Point{value.X() + value.Width(), value.Y()},
 			opencv.Point{value.X(), value.Y() + value.Height()},