diff --git a/opencv/imgproc.go b/opencv/imgproc.go
index 8139454..90ebb5c 100644
--- a/opencv/imgproc.go
+++ b/opencv/imgproc.go
@@ -16,6 +16,14 @@ import (
 	"unsafe"
 )
 
+const (
+	CV_INTER_NN       = int(C.CV_INTER_NN)
+	CV_INTER_LINEAR   = int(C.CV_INTER_LINEAR)
+	CV_INTER_CUBIC    = int(C.CV_INTER_CUBIC)
+	CV_INTER_AREA     = int(C.CV_INTER_AREA)
+	CV_INTER_LANCZOS4 = int(C.CV_INTER_LANCZOS4)
+)
+
 func Resize(src *IplImage, width, height, interpolation int) *IplImage {
 	if width == 0 && height == 0 {
 		panic("Width and Height cannot be 0 at the same time")
@@ -33,18 +41,9 @@ func Resize(src *IplImage, width, height, interpolation int) *IplImage {
 	return dst
 }
 
-func NewRect(x, y, width, height int) Rect {
-	r := C.cvRect(
-		C.int(x),
-		C.int(y),
-		C.int(width),
-		C.int(height),
-	)
-	return Rect(r)
-}
-
 func Crop(src *IplImage, x, y, width, height int) *IplImage {
-	rect := NewRect(x, y, width, height)
+	r := C.cvRect(C.int(x), C.int(y), C.int(width), C.int(height))
+	rect := Rect(r)
 
 	src.SetROI(rect)
 	dest := CreateImage(width, height, src.Depth(), src.Channels())
diff --git a/opencv/imgproc_test.go b/opencv/imgproc_test.go
new file mode 100644
index 0000000..85ed22e
--- /dev/null
+++ b/opencv/imgproc_test.go
@@ -0,0 +1,57 @@
+package opencv
+
+import (
+	"path"
+	"runtime"
+	"testing"
+)
+
+func TestResize(t *testing.T) {
+	_, currentfile, _, _ := runtime.Caller(0)
+	filename := path.Join(path.Dir(currentfile), "../images/lena.jpg")
+
+	image := LoadImage(filename)
+	if image == nil {
+		t.Fatal("LoadImage fail")
+	}
+	defer image.Release()
+
+	rimage := Resize(image, 10, 10, CV_INTER_LINEAR)
+	if rimage == nil {
+		t.Fatal("Resize fail")
+	}
+	defer rimage.Release()
+
+	if rimage.Width() != 10 {
+		t.Fatalf("excepted width is 10, returned %d\n", rimage.Width())
+	}
+
+	if rimage.Height() != 10 {
+		t.Fatalf("excepted width is 10, returned %d\n", rimage.Height())
+	}
+}
+
+func TestCrop(t *testing.T) {
+	_, currentfile, _, _ := runtime.Caller(0)
+	filename := path.Join(path.Dir(currentfile), "../images/lena.jpg")
+
+	image := LoadImage(filename)
+	if image == nil {
+		t.Fatal("LoadImage fail")
+	}
+	defer image.Release()
+
+	crop := Crop(image, 0, 0, 200, 200)
+	if crop == nil {
+		t.Fatal("Crop fail")
+	}
+	defer crop.Release()
+
+	if crop.Width() != 200 {
+		t.Fatalf("excepted width is 200, returned %d\n", crop.Width())
+	}
+
+	if crop.Height() != 200 {
+		t.Fatalf("excepted width is 200, returned %d\n", crop.Height())
+	}
+}