diff --git a/examples/matching_to_many_images/matching_to_many_images.rb b/examples/matching_to_many_images/matching_to_many_images.rb
index 0d70b1f..72d0a1c 100644
--- a/examples/matching_to_many_images/matching_to_many_images.rb
+++ b/examples/matching_to_many_images/matching_to_many_images.rb
@@ -4,9 +4,9 @@ include OpenCV
 
 data = File.dirname(__FILE__)
 
-query = IplImage.load File.join(data, 'query.png'), CV_LOAD_IMAGE_GRAYSCALE
+query = CvMat.load File.join(data, 'query.png'), CV_LOAD_IMAGE_GRAYSCALE
 image_files = ['1.png', '2.png', '3.png'].map{|f| File.join(data, 'train', f)}
-images = image_files.map{|f| IplImage.load f, CV_LOAD_IMAGE_GRAYSCALE}
+images = image_files.map{|f| CvMat.load f, CV_LOAD_IMAGE_GRAYSCALE}
 
 
 matchs = query.match_descriptors(images)
diff --git a/ext/opencv/cvmat.cpp b/ext/opencv/cvmat.cpp
index 159d7ed..6ac93da 100644
--- a/ext/opencv/cvmat.cpp
+++ b/ext/opencv/cvmat.cpp
@@ -352,6 +352,7 @@ void define_ruby_class()
   rb_define_method(rb_klass, "resize", RUBY_METHOD_FUNC(rb_resize), -1);
   rb_define_method(rb_klass, "warp_affine", RUBY_METHOD_FUNC(rb_warp_affine), -1);
   rb_define_singleton_method(rb_klass, "rotation_matrix2D", RUBY_METHOD_FUNC(rb_rotation_matrix2D), 3);
+  rb_define_singleton_method(rb_klass, "get_perspective_transform", RUBY_METHOD_FUNC(rb_get_perspective_transform), 2);
   rb_define_method(rb_klass, "warp_perspective", RUBY_METHOD_FUNC(rb_warp_perspective), -1);
   rb_define_singleton_method(rb_klass, "find_homography", RUBY_METHOD_FUNC(rb_find_homograpy), -1);
   rb_define_method(rb_klass, "remap", RUBY_METHOD_FUNC(rb_remap), -1);
@@ -4053,6 +4054,40 @@ rb_rotation_matrix2D(VALUE self, VALUE center, VALUE angle, VALUE scale)
   return map_matrix;
 }
 
+/*
+ * call-seq:
+ *   CvMat.get_perspective_transform(<i>from_points,to_points</i>) -> cvmat
+ *
+ * Calculates a perspective transform from four pairs of the corresponding points.
+ * Returns a matrix suitable for use with warp_perspective
+ */
+VALUE
+rb_get_perspective_transform(VALUE self, VALUE source, VALUE dest)
+{
+  Check_Type(source, T_ARRAY);
+  Check_Type(dest, T_ARRAY);
+
+  int count = RARRAY_LEN(source);
+
+  CvPoint2D32f* source_buff = ALLOCA_N(CvPoint2D32f, count);
+  CvPoint2D32f* dest_buff = ALLOCA_N(CvPoint2D32f, count);
+
+  for (int i = 0; i < count; i++) {
+    source_buff[i] = *(CVPOINT2D32F(RARRAY_PTR(source)[i]));
+    dest_buff[i] = *(CVPOINT2D32F(RARRAY_PTR(dest)[i]));
+  }
+
+  VALUE map_matrix = new_object(cvSize(3, 3), CV_MAKETYPE(CV_32F, 1));
+
+  try {
+    cvGetPerspectiveTransform(source_buff, dest_buff, CVMAT(map_matrix));
+  }
+  catch (cv::Exception& e) {
+    raise_cverror(e);
+  }
+  return map_matrix;
+}
+
 /*
  * call-seq:
  *   warp_perspective(<i>map_matrix[,flags = CV_INTER_LINEAR | CV_WARP_FILL_OUTLIERS][,fillval=0])</i>) -> cvmat
@@ -5351,7 +5386,6 @@ rb_match_descriptors(int argc, VALUE *argv, VALUE self)
 {
   VALUE images, detector_type, descriptor_type, matcher_type;
   rb_scan_args(argc, argv, "13", &images, &detector_type, &descriptor_type, &matcher_type);
-
   if (RARRAY_LEN(images) == 0) {
     return rb_hash_new();
   }
@@ -5365,54 +5399,58 @@ rb_match_descriptors(int argc, VALUE *argv, VALUE self)
     matcher_type = rb_str_new2("FlannBased");
   }
 
-  cv::Mat queryImage = CVMAT(self);
-  std::vector<cv::Mat> trainImages;
-  for(int i=0; i < RARRAY_LEN(images); i++) {
-    trainImages.push_back(CVMAT_WITH_CHECK(RARRAY_PTR(images)[i]));
-  }
-
-  cv::Ptr<cv::FeatureDetector> featureDetector = cv::FeatureDetector::create(RSTRING_PTR(detector_type));
-  if (featureDetector.empty()) {
-    rb_raise(rb_eArgError, "Could not create feature detector by given detector type: %s", RSTRING_PTR(detector_type));
-  }
-  cv::Ptr<cv::DescriptorExtractor> descriptorExtractor = cv::DescriptorExtractor::create(RSTRING_PTR(descriptor_type));
-  if (descriptorExtractor.empty()) {
-    rb_raise(rb_eArgError, "Could not create descriptor extractor by given descriptor type: %s", RSTRING_PTR(descriptor_type));
-  }
-  cv::Ptr<cv::DescriptorMatcher> descriptorMatcher;
-  try {
-    descriptorMatcher = cv::DescriptorMatcher::create(RSTRING_PTR(matcher_type));
-  }
-  catch(cv::Exception& e) {
-    rb_raise(rb_eArgError, "Could not create descriptor matcher by given matcher type: %s", RSTRING_PTR(matcher_type));
-  }
-
-  std::vector<cv::KeyPoint> queryKeypoints;
-  std::vector<std::vector<cv::KeyPoint> > trainKeypoints;
-  featureDetector->detect(queryImage, queryKeypoints);
-  featureDetector->detect(trainImages, trainKeypoints);
-
-  cv::Mat queryDescriptors;
-  std::vector<cv::Mat> trainDescriptors;
-  descriptorExtractor->compute(queryImage, queryKeypoints, queryDescriptors);
-  descriptorExtractor->compute(trainImages, trainKeypoints, trainDescriptors);
-
-  std::vector<cv::DMatch> matches;
-  descriptorMatcher->add(trainDescriptors);
-  descriptorMatcher->train();
-  descriptorMatcher->match(queryDescriptors, matches);
-
   VALUE _matches = rb_hash_new();
-  for (size_t i=0; i<matches.size(); i++) {
-    VALUE match = INT2FIX(matches[i].imgIdx);
-    VALUE count = rb_hash_lookup(_matches, match);
-    if (NIL_P(count)) {
-      count = INT2FIX(1);
-    } else {
-      count = INT2FIX(FIX2INT(count) + 1);
+  try {
+    cv::Mat queryImage(CVMAT(self));
+    std::vector<cv::Mat> trainImages;
+    for(int i = 0, n = RARRAY_LEN(images); i < n; i++) {
+      trainImages.push_back(CVMAT_WITH_CHECK(RARRAY_PTR(images)[i]));
+    }
+
+    cv::Ptr<cv::FeatureDetector> featureDetector = cv::FeatureDetector::create(StringValueCStr(detector_type));
+    if (featureDetector.empty()) {
+      rb_raise(rb_eArgError, "Could not create feature detector by given detector type: %s", StringValueCStr(detector_type));
+    }
+    cv::Ptr<cv::DescriptorExtractor> descriptorExtractor = cv::DescriptorExtractor::create(StringValueCStr(descriptor_type));
+    if (descriptorExtractor.empty()) {
+      rb_raise(rb_eArgError, "Could not create descriptor extractor by given descriptor type: %s", StringValueCStr(descriptor_type));
+    }
+    cv::Ptr<cv::DescriptorMatcher> descriptorMatcher;
+    try {
+      descriptorMatcher = cv::DescriptorMatcher::create(StringValueCStr(matcher_type));
+    }
+    catch(cv::Exception& e) {
+      rb_raise(rb_eArgError, "Could not create descriptor matcher by given matcher type: %s", StringValueCStr(matcher_type));
+    }
+
+    std::vector<cv::KeyPoint> queryKeypoints;
+    std::vector<std::vector<cv::KeyPoint> > trainKeypoints;
+    featureDetector->detect(queryImage, queryKeypoints);
+    featureDetector->detect(trainImages, trainKeypoints);
+    cv::Mat queryDescriptors;
+    std::vector<cv::Mat> trainDescriptors;
+    descriptorExtractor->compute(queryImage, queryKeypoints, queryDescriptors);
+    descriptorExtractor->compute(trainImages, trainKeypoints, trainDescriptors);
+    std::vector<cv::DMatch> matches;
+    descriptorMatcher->add(trainDescriptors);
+    descriptorMatcher->train();
+    descriptorMatcher->match(queryDescriptors, matches);
+
+    for (size_t i = 0, n = matches.size(); i < n; i++) {
+      VALUE match = INT2FIX(matches[i].imgIdx);
+      VALUE count = rb_hash_lookup(_matches, match);
+      if (NIL_P(count)) {
+	count = INT2FIX(1);
+      } else {
+	count = INT2FIX(FIX2INT(count) + 1);
+      }
+      rb_hash_aset(_matches, match, count);
     }
-    rb_hash_aset(_matches, match, count);
   }
+  catch (cv::Exception& e) {
+    raise_cverror(e);
+  }
+
   return _matches;
 }
 
diff --git a/ext/opencv/cvmat.h b/ext/opencv/cvmat.h
index a65bb2a..900be16 100644
--- a/ext/opencv/cvmat.h
+++ b/ext/opencv/cvmat.h
@@ -175,6 +175,7 @@ VALUE rb_quadrangle_sub_pix(int argc, VALUE *argv, VALUE self);
 VALUE rb_resize(int argc, VALUE *argv, VALUE self);
 VALUE rb_warp_affine(int argc, VALUE *argv, VALUE self);
 VALUE rb_rotation_matrix2D(VALUE self, VALUE center, VALUE angle, VALUE scale);
+VALUE rb_get_perspective_transform(VALUE self, VALUE source, VALUE dest);
 VALUE rb_warp_perspective(int argc, VALUE *argv, VALUE self);
 VALUE rb_find_homograpy(int argc, VALUE *argv, VALUE self);
 VALUE rb_remap(int argc, VALUE *argv, VALUE self);
diff --git a/test/test_cvmat_imageprocessing.rb b/test/test_cvmat_imageprocessing.rb
index e3bc9f0..05a4019 100755
--- a/test/test_cvmat_imageprocessing.rb
+++ b/test/test_cvmat_imageprocessing.rb
@@ -450,6 +450,40 @@ class TestCvMat_imageprocessing < OpenCVTestCase
     # snap mat0, mat1, mat2, mat3, mat4
   end
 
+  def test_get_perspective_transform
+    from = [
+        OpenCV::CvPoint2D32f.new(540, 382),
+        OpenCV::CvPoint2D32f.new(802, 400),
+        OpenCV::CvPoint2D32f.new(850, 731),
+        OpenCV::CvPoint2D32f.new(540, 731),
+    ]
+    to = [
+      OpenCV::CvPoint2D32f.new(0, 0),
+      OpenCV::CvPoint2D32f.new(233, 0),
+      OpenCV::CvPoint2D32f.new(233, 310),
+      OpenCV::CvPoint2D32f.new(0, 310),
+    ]
+    transform = OpenCV::CvMat.get_perspective_transform(from, to)
+    assert_equal 3, transform.rows
+    assert_equal 3, transform.columns
+    expected = [
+      0.923332154750824,
+      0.0,
+      0.0,
+      1.4432899320127035e-15,
+      0.0,
+      0.0,
+      -498.599365234375,
+      0.0,
+      0.0,
+    ]
+    3.times do |i|
+      3.times do |j|
+        assert_in_delta(expected.shift, transform[i][j], 0.001)
+      end
+    end
+  end
+
   def test_rotation_matrix2D
     mat1 = CvMat.rotation_matrix2D(CvPoint2D32f.new(10, 20), 60, 2.0)
     expected = [1.0, 1.73205, -34.64102,
diff --git a/test/test_cvmat_matching.rb b/test/test_cvmat_matching.rb
index cd50016..27d8006 100755
--- a/test/test_cvmat_matching.rb
+++ b/test/test_cvmat_matching.rb
@@ -18,7 +18,7 @@ class TestCvMat_matching < OpenCVTestCase
   end
 
   def read_test_image(*path)
-    IplImage.load File.join(data_dir, *path), CV_LOAD_IMAGE_GRAYSCALE
+    CvMat.load File.join(data_dir, *path), CV_LOAD_IMAGE_GRAYSCALE
   end
 
   def test_match_descriptors