Merge pull request #9786 from LaurentBerger:Histo3d

doc/tutorials/viz/histo3D/histo3D.markdown

+Creating a 3D histogram {#tutorial_histo3D}
+================
+
+Goal
+----
+
+In this tutorial you will learn how to
+
+-   Create your own callback keyboard function for viz window.
+-   Show your 3D histogram in a viz window.
+
+Code
+----
+
+You can download the code from [here ](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/viz/histo3D.cpp).
+@include samples/cpp/tutorial_code/viz/histo3D.cpp
+
+Explanation
+-----------
+
+Here is the general structure of the program:
+
+-   You can give full path to an image in command line
+    @snippet histo3D.cpp command_line_parser
+
+    or without path, a synthetic image is generated with pixel values are a gaussian distribution @ref cv::RNG::fill center(60+/-10,40+/-5,50+/-20) in first quadrant,
+    (160+/-20,10+/-5,50+/-10) in second quadrant, (90+/-10,100+/-20,50+/-20) in third quadrant, (100+/-10,10+/-5,150+/-40) in last quadrant.
+    @snippet histo3D.cpp synthetic_image
+    Image tridimensional histogram is calculated using opencv @ref cv::calcHist and @ref cv::normalize between 0 and 100.
+    @snippet histo3D.cpp calchist_for_histo3d
+    channel are 2, 1 and 0 to synchronise color with Viz axis color in objetc cv::viz::WCoordinateSystem.
+
+    A slidebar is inserted in image window. Init slidebar value is 90, it means that only histogram cell greater than 9/100000.0 (23 pixels for an 512X512 pixels) will be display.
+    @snippet histo3D.cpp slide_bar_for_thresh
+    We are ready to open a viz window with a callback function to capture keyboard event in viz window. Using @ref cv::viz::Viz3d::spinOnce enable keyboard event to be capture in @ref cv::imshow window too.
+    @snippet histo3D.cpp manage_viz_imshow_window
+    The function DrawHistogram3D processes histogram Mat to display it in a Viz window. Number of plan, row and column in [three dimensional Mat](@ref CVMat_Details ) can be found using  this code :
+    @snippet histo3D.cpp get_cube_size
+    To get histogram value at a specific location we use @ref cv::Mat::at(int i0,int i1, int i2)  method with three arguments k, i and j where k is plane number, i row number and j column number.
+    @snippet histo3D.cpp get_cube_values
+
+-   Callback function
+    Principle are as mouse callback function. Key code pressed is in field code of class @ref cv::viz::KeyboardEvent.
+    @snippet histo3D.cpp viz_keyboard_callback
+
+Results
+-------
+
+Here is the result of the program with no argument and threshold equal to 50.
+
+![](images/histo50.png)

doc/tutorials/viz/table_of_content_viz.markdown

@@ -32,3 +32,11 @@ OpenCV Viz {#tutorial_table_of_content_viz}
     *Author:* Ozan Tonkal
 
     You will learn how to create your own widgets.
+
+-   @subpage tutorial_histo3D
+
+    *Compatibility:* \> OpenCV 3.0.0
+
+    *Author:* Laurent Berger
+
+    You will learn how to plot a 3D histogram.

modules/core/include/opencv2/core/mat.hpp

@@ -582,7 +582,7 @@ protected:
 An example demonstrating the serial out capabilities of cv::Mat
 */
 
- /** @brief n-dimensional dense array class
+ /** @brief n-dimensional dense array class \anchor CVMat_Details
 
 The class Mat represents an n-dimensional dense numerical single-channel or multi-channel array. It
 can be used to store real or complex-valued vectors and matrices, grayscale or color images, voxel

samples/cpp/tutorial_code/viz/histo3D.cpp

+#include <opencv2/opencv.hpp>
+#include <iostream>
+
+using namespace std;
+using namespace cv;
+
+#ifdef HAVE_OPENCV_VIZ
+
+const String keys =
+"{Aide h usage ? help  |     | print this message   }"
+"{@arg1                |     | Full path to color imag (3 channels)}"
+;
+
+
+struct Histo3DData {
+    Mat histogram;
+    int seuil;
+    double threshold;
+    Ptr<viz::Viz3d> fen3D;
+    int nbWidget;
+    bool status;
+    double maxH;
+    int code;
+};
+
+void DrawHistogram3D(Histo3DData &);
+void AddSlidebar(String sliderName, String windowName, int sliderMin, int sliderMax, int valeurDefaut, int *sliderVal, void(*f)(int, void *), void *r);
+void UpdateThreshold(int , void * r);
+void  KeyboardViz3d(const viz::KeyboardEvent &w, void *t);
+
+
+void DrawHistogram3D(Histo3DData &h)
+{
+    //! [get_cube_size]
+    int planSize = h.histogram.step1(0);
+    int cols = h.histogram.step1(1);
+    int rows = planSize / cols;
+    int plans = h.histogram.total() / planSize;
+    h.fen3D->removeAllWidgets();
+    h.nbWidget=0;
+    if (h.nbWidget==0)
+        h.fen3D->showWidget("Axis", viz::WCoordinateSystem(10));
+    //! [get_cube_size]
+    //! [get_cube_values]
+    for (int k = 0; k < plans; k++)
+    {
+        for (int i = 0; i < rows; i++)
+        {
+            for (int j = 0; j < cols; j++)
+            {
+                double x = h.histogram.at<float>(k, i, j);
+                if (x >= h.threshold)
+                {
+                    double r=std::max(x/h.maxH,0.1);
+                    viz::WCube s(Point3d(k - r / 2, i - r / 2, j - r / 2), Point3d(k + r / 2, i + r / 2, j + r / 2), false, viz::Color(j / double(plans) * 255, i / double(rows) * 255, k / double(cols) * 255));
+                    h.fen3D->showWidget(format("I3d%d", h.nbWidget++), s);
+                }
+            }
+        }
+    }
+    //! [get_cube_values]
+    h.status = false;
+}
+//! [viz_keyboard_callback]
+void  KeyboardViz3d(const viz::KeyboardEvent &w, void *t)
+{
+   Histo3DData *x=(Histo3DData *)t;
+   if (w.action)
+       cout << "you pressed "<< w.symbol<< " in viz window "<<x->fen3D->getWindowName()<<"\n";
+   x->code= w.code;
+   switch (w.code) {
+   case '/':
+           x->status=true;
+           x->threshold *= 0.9;
+       break;
+   case '*':
+       x->status = true;
+           x->threshold *= 1.1;
+       break;
+    }
+   if (x->status)
+   {
+       cout <<  x->threshold << "\n";
+       DrawHistogram3D(*x);
+   }
+}
+//! [viz_keyboard_callback]
+
+
+void AddSlidebar(String sliderName, String windowName, int sliderMin, int sliderMax, int defaultSlider, int *sliderVal, void(*f)(int, void *), void *r)
+{
+    createTrackbar(sliderName, windowName, sliderVal, 1, f, r);
+    setTrackbarMin(sliderName, windowName, sliderMin);
+    setTrackbarMax(sliderName, windowName, sliderMax);
+    setTrackbarPos(sliderName, windowName, defaultSlider);
+}
+
+
+void UpdateThreshold(int , void * r)
+{
+    Histo3DData *h = (Histo3DData *)r;
+    h->status=true;
+    h->threshold = h->seuil/1000000.0;
+    cout<<"Widget : "<<h->nbWidget<<","<< h->threshold<<"\n";
+}
+
+int main (int argc,char **argv)
+{
+    //! [command_line_parser]
+    CommandLineParser parser(argc, argv, keys);
+
+    if (parser.has("help"))
+    {
+        parser.printMessage();
+        return 0;
+    }
+    String nomFic = parser.get<String>(0);
+    Mat img;
+    if (nomFic.length() != 0)
+    {
+        img = imread(nomFic, IMREAD_COLOR);
+        if (img.empty())
+        {
+            cout << "Image does not exist!";
+            return 0;
+        }
+    }
+    //! [command_line_parser]
+    //! [synthetic_image]
+    else
+    {
+        img = Mat(512,512,CV_8UC3);
+        parser.printMessage();
+        RNG r;
+        r.fill(img(Rect(0, 0, 256, 256)), RNG::NORMAL, Vec3b(60, 40, 50), Vec3b(10, 5, 20));
+        r.fill(img(Rect(256, 0, 256, 256)), RNG::NORMAL, Vec3b(160, 10, 50), Vec3b(20, 5, 10));
+        r.fill(img(Rect(0, 256, 256, 256)), RNG::NORMAL, Vec3b(90, 100, 50), Vec3b(10, 20, 20));
+        r.fill(img(Rect(256, 256, 256, 256)), RNG::NORMAL, Vec3b(100, 10, 150), Vec3b(10, 5, 40));
+    }
+    //! [synthetic_image]
+    //! [calchist_for_histo3d]
+    Histo3DData h;
+    h.status=true;
+    h.seuil=90;
+    h.threshold= h.seuil/1000000.0;
+    float hRange[] = { 0, 256 };
+    const float* etendu[] = { hRange, hRange,hRange };
+    int hBins = 32;
+    int histSize[] = { hBins, hBins , hBins  };
+    int channel[] = { 2, 1,0 };
+    calcHist(&img, 1, channel, Mat(), h.histogram, 3, histSize, etendu, true, false);
+    normalize(h.histogram, h.histogram, 100.0/(img.total()), 0, NORM_MINMAX, -1, Mat());
+    minMaxIdx(h.histogram,NULL,&h.maxH,NULL,NULL);
+    //! [calchist_for_histo3d]
+    //! [slide_bar_for_thresh]
+    namedWindow("Image");
+    imshow("Image",img);
+    AddSlidebar("threshold","Image",0,100,h.seuil,&h.seuil, UpdateThreshold,&h);
+    waitKey(30);
+    //! [slide_bar_for_thresh]
+    //! [manage_viz_imshow_window]
+    h.fen3D = new viz::Viz3d("3D Histogram");
+    h.nbWidget=0;
+    h.fen3D->registerKeyboardCallback(KeyboardViz3d,&h);
+    DrawHistogram3D(h);
+    while (h.code!=27)
+    {
+        h.fen3D->spinOnce(1);
+        if (h.status)
+            DrawHistogram3D(h);
+        if (h.code!=27)
+            h.code= waitKey(30);
+    }
+    //! [manage_viz_imshow_window]
+    return 0;
+}
+#else
+
+int main(int argc, char **argv)
+{
+cout << " you need VIZ module\n";
+return 0;
+}
+#endif