Implementation of Global sampling based matting

modules/ximgproc/README.md

@@ -16,3 +16,4 @@ Extended Image Processing
 - Pei&Lin Normalization
 - Ridge Detection Filter
 - Binary morphology on run-length encoded images
+- Global sampling based method for alpha matting

modules/ximgproc/include/opencv2/ximgproc.hpp

@@ -59,6 +59,7 @@
 #include "ximgproc/run_length_morphology.hpp"
 #include "ximgproc/edgepreserving_filter.hpp"
 #include "ximgproc/color_match.hpp"
+#include "ximgproc/globalmatting.hpp"
 
 
 /** @defgroup ximgproc Extended Image Processing

modules/ximgproc/include/opencv2/ximgproc/globalmatting.hpp

@@ -0,0 +1,28 @@
+// 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.
+#ifndef __OPENCV_XIMGPROC_GLOBAL_MATTING_HPP__
+#define __OPENCV_XIMGPROC_GLOBAL_MATTING_HPP__
+
+#include <opencv2/imgproc.hpp>
+#include <opencv2/ximgproc/edge_filter.hpp>
+
+
+namespace cv { namespace ximgproc {
+
+class CV_EXPORTS GlobalMatting
+{
+public:
+    GlobalMatting();
+    virtual ~GlobalMatting();
+
+    virtual void globalMatting(InputArray image, InputArray trimap, OutputArray foreground, OutputArray alpha, OutputArray conf = noArray()) = 0;
+
+    virtual void getMat(InputArray image, InputArray trimap, OutputArray foreground, OutputArray alpha, int niter=9) = 0;
+};
+
+CV_EXPORTS Ptr<GlobalMatting> createGlobalMatting();
+
+}}  // namespace
+
+#endif  // __OPENCV_XIMGPROC_GLOBAL_MATTING_HPP__

modules/ximgproc/samples/globalmatting.cpp

@@ -0,0 +1,51 @@
+#include <opencv2/ximgproc.hpp>
+#include <iostream>
+#include <opencv2/core.hpp>
+#include <opencv2/highgui.hpp>
+
+using namespace std;
+using namespace cv;
+using namespace ximgproc;
+
+int main(int argc, char** argv)
+{
+    if (argc < 3)
+    {
+        cout << "arg1: location of input image" << endl;
+        cout << "arg2: location of its trimap" << endl;
+        cout << "arg3(optional): number of iterations to run expansion of trimap" << endl;
+        return -1;
+    }
+    string img_path = argv[1];
+    string tri_path = argv[2];
+    int niter = 9;
+    if (argc == 4)
+    {
+        niter = atoi(argv[3]);
+    }
+    Mat image = imread(img_path, IMREAD_COLOR);
+    Mat trimap = imread(tri_path, IMREAD_GRAYSCALE);
+    if (image.empty() || trimap.empty())
+    {
+        cout << "Could not load the inputs" << endl;
+        return -2;
+    }
+    // (optional) exploit the affinity of neighboring pixels to reduce the
+    // size of the unknown region. please refer to the paper
+    // 'Shared Sampling for Real-Time Alpha Matting'.
+
+    Mat foreground, alpha;
+
+    Ptr<GlobalMatting> gm = createGlobalMatting();
+
+    gm->getMat(image, trimap, foreground, alpha, niter);
+
+    imwrite("alpha-matte.png", alpha);
+
+    imshow("input", image);
+    imshow("trimap", trimap);
+    imshow("alpha-matte", alpha);
+    waitKey();
+
+    return 0;
+}