diff --git a/ext/opencv/mat.cpp b/ext/opencv/mat.cpp
index 22a0136..da0da4b 100644
--- a/ext/opencv/mat.cpp
+++ b/ext/opencv/mat.cpp
@@ -1234,6 +1234,7 @@ namespace rubyopencv {
       rb_define_method(rb_klass, "sobel", RUBY_METHOD_FUNC(rb_sobel), -1); // in ext/opencv/mat_imgproc.cpp
       rb_define_method(rb_klass, "sobel!", RUBY_METHOD_FUNC(rb_sobel_bang), -1); // in ext/opencv/mat_imgproc.cpp
       rb_define_method(rb_klass, "canny", RUBY_METHOD_FUNC(rb_canny), -1); // in ext/opencv/mat_imgproc.cpp
+      rb_define_method(rb_klass, "canny!", RUBY_METHOD_FUNC(rb_canny_bang), -1); // in ext/opencv/mat_imgproc.cpp
       rb_define_method(rb_klass, "laplacian", RUBY_METHOD_FUNC(rb_laplacian), -1); // in ext/opencv/mat_imgproc.cpp
 
       rb_define_method(rb_klass, "line", RUBY_METHOD_FUNC(rb_line), -1); // in ext/opencv/mat_drawing.cpp
diff --git a/ext/opencv/mat_imgproc.cpp b/ext/opencv/mat_imgproc.cpp
index 6411562..249561b 100644
--- a/ext/opencv/mat_imgproc.cpp
+++ b/ext/opencv/mat_imgproc.cpp
@@ -67,19 +67,7 @@ namespace rubyopencv {
       return self;
     }
 
-    /**
-     * Finds edges in an image using the [Canny86] algorithm.
-     *
-     * @overload canny(threshold1, threshold2, aperture_size = 3, l2gradient = false)
-     *   @param threshold1 [Number] First threshold for the hysteresis procedure.
-     *   @param threshold2 [Number] Second threshold for the hysteresis procedure.
-     *   @param aperture_size [Integer] Aperture size for the Sobel operator.
-     *   @param l2gradient [Boolean] a flag, indicating whether a more accurate L_2 =\sqrt{ (dI/dx)^2 + (dI/dy)^2 } norm
-     *     should be used to calculate the image gradient magnitude (l2gradient=true),
-     *     or whether the default L_1 norm =|dI/dx|+|dI/dy| is enough (l2gradient=false).
-     * @opencv_func cv::Canny
-     */
-    VALUE rb_canny(int argc, VALUE *argv, VALUE self) {
+    cv::Mat* rb_canny_internal(int argc, VALUE *argv, VALUE self, cv::Mat* destptr) {
       VALUE threshold1, threshold2, aperture_size, l2gradient;
       rb_scan_args(argc, argv, "22", &threshold1, &threshold2, &aperture_size, &l2gradient);
 
@@ -87,10 +75,29 @@ namespace rubyopencv {
       bool l2gradient_value = RTEST(l2gradient) ? true : false;
 
       cv::Mat* selfptr = obj2mat(self);
+      cv::Canny(*selfptr, *destptr, NUM2DBL(threshold1), NUM2DBL(threshold2),
+		aperture_size_value, l2gradient_value);
+
+      return destptr;
+    }
+
+    /**
+     * Finds edges in an image using the [Canny86] algorithm.
+     *
+     * @overload canny(threshold1, threshold2, aperture_size = 3, l2gradient = false)
+     *   @param threshold1 [Number] First threshold for the hysteresis procedure.
+     *   @param threshold2 [Number] Second threshold for the hysteresis procedure.
+     *   @param aperture_size [Integer] Aperture size for the Sobel operator.
+     *   @param l2gradient [Boolean] a flag, indicating whether a more accurate L_2 = \sqrt{ (dI/dx)^2 + (dI/dy)^2 } norm
+     *     should be used to calculate the image gradient magnitude (l2gradient=true),
+     *     or whether the default L_1 norm = |dI/dx|+|dI/dy| is enough (l2gradient=false).
+     * @return [Mat] Output image
+     * @opencv_func cv::Canny
+     */
+    VALUE rb_canny(int argc, VALUE *argv, VALUE self) {
       cv::Mat* destptr = new cv::Mat();
       try {
-	cv::Canny(*selfptr, *destptr, NUM2DBL(threshold1), NUM2DBL(threshold2),
-		  aperture_size_value, l2gradient_value);
+	rb_canny_internal(argc, argv, self, destptr);
       }
       catch (cv::Exception& e) {
 	delete destptr;
@@ -100,6 +107,22 @@ namespace rubyopencv {
       return mat2obj(destptr, CLASS_OF(self));
     }
 
+    /**
+     * @overload canny!(threshold1, threshold2, aperture_size = 3, l2gradient = false)
+     * @see #canny
+     */
+    VALUE rb_canny_bang(int argc, VALUE *argv, VALUE self) {
+      cv::Mat* destptr = obj2mat(self);
+      try {
+	rb_canny_internal(argc, argv, self, destptr);
+      }
+      catch (cv::Exception& e) {
+	Error::raise(e);
+      }
+
+      return self;
+    }
+
     /*
      * Calculates the Laplacian of an image.
      *
diff --git a/ext/opencv/mat_imgproc.hpp b/ext/opencv/mat_imgproc.hpp
index 3861c73..5583f97 100644
--- a/ext/opencv/mat_imgproc.hpp
+++ b/ext/opencv/mat_imgproc.hpp
@@ -9,6 +9,7 @@ namespace rubyopencv {
     VALUE rb_sobel(int argc, VALUE *argv, VALUE self);
     VALUE rb_sobel_bang(int argc, VALUE *argv, VALUE self);
     VALUE rb_canny(int argc, VALUE *argv, VALUE self);
+    VALUE rb_canny_bang(int argc, VALUE *argv, VALUE self);
     VALUE rb_laplacian(int argc, VALUE *argv, VALUE self);
     VALUE rb_cvt_color(int argc, VALUE *argv, VALUE self);
     VALUE rb_resize(int argc, VALUE *argv, VALUE self);
diff --git a/test/test_mat_imgproc.rb b/test/test_mat_imgproc.rb
index 310a562..644b6cb 100755
--- a/test/test_mat_imgproc.rb
+++ b/test/test_mat_imgproc.rb
@@ -123,6 +123,41 @@ class TestCvMat < OpenCVTestCase
     # Cv::wait_key
   end
 
+  def test_canny_bang
+    m0 = Cv::imread(FILENAME_LENA256x256, 0)
+    m1 = m0.clone
+    m0.canny!(50, 200)
+    m1.canny!(50, 200, 5, true)
+
+    canny = [m0, m1]
+    canny.each { |m|
+      assert_equal(m0.rows, m.rows)
+      assert_equal(m0.cols, m.cols)
+      assert_equal(m0.depth, m.depth)
+      assert_equal(m0.dims, m.dims)
+      assert_equal(m0.channels, m.channels)
+    }
+
+    assert_raise(TypeError) {
+      m0.canny!(DUMMY_OBJ, 200, 5, true)
+    }
+    assert_raise(TypeError) {
+      m0.canny!(50, DUMMY_OBJ, 5, true)
+    }
+    assert_raise(TypeError) {
+      m0.canny!(50, 200, DUMMY_OBJ, true)
+    }
+    assert_nothing_raised {
+      m0.canny!(50, 200, 5, DUMMY_OBJ)
+    }
+
+    # w = Window.new('Canny')
+    # m0 = Cv::imread(FILENAME_LENA256x256, 0)
+    # m0.canny!(50, 200)
+    # w.show(m0)
+    # Cv::wait_key
+  end
+
   def test_laplacian
     m0 = Cv::imread(FILENAME_LENA256x256, 0)