add a slic superpixels sample, similar to the seeds one.

modules/ximgproc/samples/slic.cpp

+#include <opencv2/imgproc.hpp>
+#include <opencv2/highgui.hpp>
+#include <opencv2/imgcodecs.hpp>
+#include <opencv2/core/utility.hpp>
+
+#include <opencv2/ximgproc.hpp>
+
+#include <ctype.h>
+#include <stdio.h>
+#include <iostream>
+
+using namespace cv;
+using namespace cv::ximgproc;
+using namespace std;
+
+static const char* window_name = "SLIC Superpixels";
+
+static const char* keys =
+    "{h help      | | help menu}"
+    "{c camera    |0| camera id}"
+    "{i image     | | image file}"
+    "{a algorithm |1| SLIC(0),SLICO(1)}"
+    ;
+
+int main(int argc, char** argv)
+{
+    CommandLineParser cmd(argc,argv,keys);
+    if (cmd.has("help")) {
+        cmd.about("This program demonstrates SLIC superpixels using OpenCV class SuperpixelSLIC.\n"
+            "If no image file is supplied, try to open a webcam.\n"
+            "Use [space] to toggle output mode, ['q' or 'Q' or 'esc'] to exit.\n");
+        cmd.printMessage();
+        return 0;
+    }
+    int capture = cmd.get<int>("camera");
+    String img_file = cmd.get<String>("image");
+    int algorithm = cmd.get<int>("algorithm");
+    int region_size = 50;
+    int ruler = 30;
+    int min_element_size = 50;
+    int num_iterations = 3;
+    bool use_video_capture = img_file.empty();
+
+    VideoCapture cap;
+    Mat input_image;
+
+    if( use_video_capture )
+    {
+        if( !cap.open(capture) )
+        {
+            cout << "Could not initialize capturing..."<<capture<<"\n";
+            return -1;
+        }
+    }
+    else
+    {
+        input_image = imread(img_file);
+        if( input_image.empty() )
+        {
+            cout << "Could not open image..."<<img_file<<"\n";
+            return -1;
+        }
+    }
+
+    namedWindow(window_name, 0);
+    createTrackbar("Algorithm", window_name, &algorithm, 1, 0);
+    createTrackbar("Region size", window_name, &region_size, 200, 0);
+    createTrackbar("Ruler", window_name, &ruler, 100, 0);
+    createTrackbar("Connectivity", window_name, &min_element_size, 100, 0);
+    createTrackbar("Iterations", window_name, &num_iterations, 12, 0);
+
+    Mat result, mask;
+    int display_mode = 0;
+
+    for (;;)
+    {
+        Mat frame;
+        if( use_video_capture )
+            cap >> frame;
+        else
+            input_image.copyTo(frame);
+
+        if( frame.empty() )
+            break;
+
+        result = frame;
+        Mat converted;
+        cvtColor(frame, converted, COLOR_BGR2HSV);
+
+        double t = (double) getTickCount();
+
+        Ptr<SuperpixelSLIC> slic = createSuperpixelSLIC(converted,algorithm+SLIC,region_size,float(ruler));
+        slic->iterate(num_iterations);
+        if (min_element_size>0)
+            slic->enforceLabelConnectivity(min_element_size);
+
+        t = ((double) getTickCount() - t) / getTickFrequency();
+        cout << "SLIC" << (algorithm?'O':' ')
+             << " segmentation took " << (int) (t * 1000)
+             << " ms with " << slic->getNumberOfSuperpixels() << " superpixels" << endl;
+
+        // get the contours for displaying
+        slic->getLabelContourMask(mask, true);
+        result.setTo(Scalar(0, 0, 255), mask);
+
+        // display output
+        switch (display_mode)
+        {
+        case 0: //superpixel contours
+            imshow(window_name, result);
+            break;
+        case 1: //mask
+            imshow(window_name, mask);
+            break;
+        case 2: //labels array
+        {
+            // use the last x bit to determine the color. Note that this does not
+            // guarantee that 2 neighboring superpixels have different colors.
+            // retrieve the segmentation result
+            Mat labels;
+            slic->getLabels(labels);
+            const int num_label_bits = 2;
+            labels &= (1 << num_label_bits) - 1;
+            labels *= 1 << (16 - num_label_bits);
+            imshow(window_name, labels);
+            break;
+        }
+        }
+
+        int c = waitKey(1) & 0xff;
+        if( c == 'q' || c == 'Q' || c == 27 )
+            break;
+        else if( c == ' ' )
+            display_mode = (display_mode + 1) % 3;
+    }
+
+    return 0;
+}