Ridge Filter

modules/README.md

@@ -62,7 +62,7 @@ $ cmake -D OPENCV_EXTRA_MODULES_PATH=<opencv_contrib>/modules -D BUILD_opencv_<r
 
 - **xfeatures2d**: Features2D extra -- Extra 2D Features Framework containing experimental and non-free 2D feature detector/descriptor algorithms. SURF, SIFT, BRIEF, Censure, Freak, LUCID, Daisy, Self-similar.
 
-- **ximgproc**: Extended Image Processing -- Structured Forests / Domain Transform Filter / Guided Filter / Adaptive Manifold Filter / Joint Bilateral Filter / Superpixels.
+- **ximgproc**: Extended Image Processing -- Structured Forests / Domain Transform Filter / Guided Filter / Adaptive Manifold Filter / Joint Bilateral Filter / Superpixels / Ridge Detection Filter.
 
 - **xobjdetect**: Boosted 2D Object Detection -- Uses a Waldboost cascade and local binary patterns computed as integral features for 2D object detection.
 

modules/ximgproc/README.md

@@ -14,3 +14,4 @@ Extended Image Processing
 - Fast Line Detector
 - Deriche Filter
 - Pei&Lin Normalization
+- Ridge Detection Filter

modules/ximgproc/include/opencv2/ximgproc.hpp

@@ -54,6 +54,7 @@
 #include "ximgproc/deriche_filter.hpp"
 #include "ximgproc/peilin.hpp"
 #include "ximgproc/fourier_descriptors.hpp"
+#include "ximgproc/ridgefilter.hpp"
 
 
 /** @defgroup ximgproc Extended Image Processing

modules/ximgproc/include/opencv2/ximgproc/ridgefilter.hpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+/*
+Ridge Detection Filter.
+OpenCV port by : Kushal Vyas (@kushalvyas), Venkatesh Vijaykumar(@venkateshvijaykumar)
+*/
+
+#ifndef __OPENCV_XIMGPROC_RIDGEFILTER_HPP__
+#define __OPENCV_XIMGPROC_RIDGEFILTER_HPP__
+
+#include <opencv2/core.hpp>
+
+namespace cv { namespace ximgproc {
+
+//! @addtogroup ximgproc_filters
+//! @{
+
+/** @brief  Applies Ridge Detection Filter to an input image.
+Implements Ridge detection similar to the one in [Mathematica](http://reference.wolfram.com/language/ref/RidgeFilter.html)
+using the eigen values from the Hessian Matrix of the input image using Sobel Derivatives.
+Additional refinement can be done using Skeletonization and Binarization.
+*/
+class CV_EXPORTS_W RidgeDetectionFilter : public Algorithm
+{
+public:
+    /**
+    @brief Create pointer to the Ridge detection filter.
+    @param ddepth  Specifies output image depth. Defualt is CV_32FC1
+    @param dx Order of derivative x, default is 1
+    @param dy  Order of derivative y, default is 1
+    @param ksize Sobel kernel size , default is 3
+    @param out_dtype Converted format for output, default is CV_8UC1
+    @param scale Optional scale value for derivative values, default is 1
+    @param delta  Optional bias added to output, default is 0
+    @param borderType Pixel extrapolation method, default is BORDER_DEFAULT
+    @see Sobel, threshold, getStructuringElement, morphologyEx.( for additional refinement)
+    */
+    CV_WRAP static Ptr<RidgeDetectionFilter> create(int ddepth = CV_32FC1, int dx=1, int dy=1, int ksize = 3, int out_dtype=CV_8UC1, double scale = 1, double delta = 0, int borderType = BORDER_DEFAULT);
+    /**
+    @brief Apply Ridge detection filter on input image.
+    @param _img InputArray as supported by Sobel. img can be 1-Channel or 3-Channels.
+    @param out OutputAray of structure as RidgeDetectionFilter::ddepth. Output image with ridges.
+    */
+    CV_WRAP virtual void getRidgeFilteredImage(InputArray _img, OutputArray out) = 0;
+};
+
+//! @}
+}} // namespace
+#endif

modules/ximgproc/perf/perf_ridge_detection_filter.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+#include "perf_precomp.hpp"
+
+namespace cvtest {
+
+using namespace perf;
+using namespace testing;
+using namespace cv;
+using namespace cv::ximgproc;
+
+typedef tuple<MatDepth, int, Size> RDFParams;
+typedef TestBaseWithParam<RDFParams> RidgeDetectionFilterPerfTest;
+
+PERF_TEST_P(RidgeDetectionFilterPerfTest, perf, Combine(
+        Values((MatDepth)CV_32F),
+        Values(3),
+        SZ_TYPICAL
+))
+{
+    RDFParams params = GetParam();
+    int ddepth = get<0>(params);
+    int ksize = get<1>(params);
+    Size sz = get<2>(params);
+
+    Mat src(sz, ddepth);
+    Mat out(sz, src.type());
+
+    declare.in(src).out(out);
+
+    Ptr<RidgeDetectionFilter> rdf = RidgeDetectionFilter::create(ddepth,1, 1, ksize);
+
+    TEST_CYCLE() rdf->getRidgeFilteredImage(src, out);
+
+    SANITY_CHECK_NOTHING();
+}
+
+} // namespace

modules/ximgproc/src/ridgedetectionfilter.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "precomp.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/ximgproc/ridgefilter.hpp"
+
+namespace cv { namespace ximgproc {
+
+class RidgeDetectionFilterImpl : public RidgeDetectionFilter
+{
+public:
+    int _ddepth, _dx, _dy, _ksize;
+    double _scale, _delta;
+    int _borderType;
+    int _out_dtype;
+    RidgeDetectionFilterImpl(int ddepth=CV_32FC1, int dx=1, int dy=1, int ksize = 3, int out_dtype=CV_8UC1, double scale = 1, double delta = 0, int borderType = BORDER_DEFAULT)
+    {
+        CV_Assert((ksize == 1 || ksize == 3 || ksize == 5 || ksize == 7));
+        CV_Assert((ddepth == CV_32FC1 || ddepth == CV_64FC1));
+        _ddepth = ddepth;
+        _dx = dx;
+        _dy = dy;
+        _ksize = ksize;
+        _scale = scale;
+        _delta = delta;
+        _borderType = borderType;
+        _out_dtype = out_dtype;
+    }
+    virtual void getRidgeFilteredImage(InputArray _img, OutputArray out);
+};
+
+void RidgeDetectionFilterImpl::getRidgeFilteredImage(InputArray _img, OutputArray out)
+{
+    Mat img = _img.getMat();
+    CV_Assert(img.channels() == 1 || img.channels() == 3);
+
+    if(img.channels() == 3)
+        cvtColor(img, img, COLOR_BGR2GRAY);
+
+    Mat sbx, sby;
+    Sobel(img, sbx, _ddepth, _dx, 0, _ksize, _scale, _delta, _borderType);
+    Sobel(img, sby, _ddepth, 0, _dy, _ksize, _scale, _delta, _borderType);
+
+    Mat sbxx, sbyy, sbxy;
+    Sobel(sbx, sbxx, _ddepth, _dx, 0, _ksize, _scale, _delta, _borderType);
+    Sobel(sby, sbyy, _ddepth, 0, _dy, _ksize, _scale, _delta, _borderType);
+    Sobel(sbx, sbxy, _ddepth, 0, _dy, _ksize, _scale, _delta, _borderType);
+
+    Mat sb2xx, sb2yy, sb2xy;
+    multiply(sbxx, sbxx, sb2xx);
+    multiply(sbyy, sbyy, sb2yy);
+    multiply(sbxy, sbxy, sb2xy);
+
+    Mat sbxxyy;
+    multiply(sbxx, sbyy, sbxxyy);
+
+    Mat rootex;
+    rootex = (sb2xx +  (sb2xy + sb2xy + sb2xy + sb2xy)  - (sbxxyy + sbxxyy) + sb2xy );
+    Mat root;
+    sqrt(rootex, root);
+    Mat ridgexp;
+    ridgexp = ( (sbxx + sbyy) + root );
+    ridgexp.convertTo(out, _out_dtype, 0.5);
+}
+
+Ptr<RidgeDetectionFilter> RidgeDetectionFilter::create(int ddepth, int dx, int dy, int ksize, int out_dtype, double scale, double delta, int borderType)
+{
+    return makePtr<RidgeDetectionFilterImpl>(ddepth, dx, dy, ksize, out_dtype, scale, delta, borderType);
+}
+
+}} // namespace

modules/ximgproc/test/test_ridge_detection_filter.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "test_precomp.hpp"
+
+namespace cvtest {
+
+using namespace cv;
+using namespace cv::ximgproc;
+
+TEST(ximgproc_ridgedetectionfilter, ReferenceAccuracy)
+{
+    String openCVExtraDir = cvtest::TS::ptr()->get_data_path();
+    String srcImgPath = "cv/ximgproc/sources/04.png";
+    String refPath = "cv/ximgproc/results/ridge_filter_test_ref/04.png";
+    Mat src = imread(openCVExtraDir + srcImgPath);
+    Mat ref = imread(openCVExtraDir + refPath, 0);
+    Mat n_ref;
+    ref.convertTo(n_ref, CV_8UC1);
+    Ptr<RidgeDetectionFilter> rdf = RidgeDetectionFilter::create();
+    Mat out;
+    rdf->getRidgeFilteredImage(src, out);
+    Mat out_cmp;
+    out.convertTo(out_cmp, CV_8UC1);
+    Mat sb;
+    subtract(out_cmp, n_ref, sb);
+    int zeros = countNonZero(sb);
+    EXPECT_EQ(zeros, 0);
+}
+
+} // namespace