Minor refactoring in several C++ samples:

- bgfg_segm
- peopledetect
- opencv_version
- dnn/colorization
- tapi/opencl_custom_kernel
- tapi/dense_optical_flow (renamed tvl1_optical_flow)

Author: mshabunin

samples/cpp/bgfg_segm.cpp

@@ -1,3 +1,7 @@
+// 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 "opencv2/core.hpp"
 #include "opencv2/imgproc.hpp"
 #include "opencv2/video.hpp"
@@ -10,18 +14,18 @@ using namespace cv;
 
 int main(int argc, const char** argv)
 {
-    const String keys = "{c camera||use video stream from camera (default is NO)}"
-                        "{fn file_name|../data/tree.avi|video file}"
-                        "{m method|mog2|method: background subtraction algorithm ('knn', 'mog2')}"
-                        "{h help||show help message}";
+    const String keys = "{c camera     | 0 | use video stream from camera (device index starting from 0) }"
+                        "{fn file_name |   | use video file as input }"
+                        "{m method | mog2 | method: background subtraction algorithm ('knn', 'mog2')}"
+                        "{h help | | show help message}";
     CommandLineParser parser(argc, argv, keys);
     parser.about("This sample demonstrates background segmentation.");
     if (parser.has("help"))
     {
         parser.printMessage();
         return 0;
     }
-    bool useCamera = parser.has("camera");
+    int camera = parser.get<int>("camera");
     String file = parser.get<String>("file_name");
     String method = parser.get<String>("method");
     if (!parser.check())
@@ -31,13 +35,13 @@ int main(int argc, const char** argv)
     }
 
     VideoCapture cap;
-    if (useCamera)
-        cap.open(0);
+    if (file.empty())
+        cap.open(camera);
     else
         cap.open(file.c_str());
     if (!cap.isOpened())
     {
-        cout << "Can not open video stream: '" << (useCamera ? "<camera 0>" : file) << "'" << endl;
+        cout << "Can not open video stream: '" << (file.empty() ? "<camera>" : file) << "'" << endl;
         return 2;
     }
 

samples/cpp/opencv_version.cpp

@@ -1,16 +1,17 @@
+// 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 <opencv2/core/utility.hpp>
 #include <iostream>
 
-const char* keys =
-{
-    "{ b build | | print complete build info }"
-    "{ h help  | | print this help           }"
-};
+static const std::string keys = "{ b build | | print complete build info }"
+                                "{ h help  | | print this help           }";
 
 int main(int argc, const char* argv[])
 {
     cv::CommandLineParser parser(argc, argv, keys);
-
+    parser.about("This sample outputs OpenCV version and build configuration.");
     if (parser.has("help"))
     {
         parser.printMessage();
@@ -27,6 +28,5 @@ int main(int argc, const char* argv[])
     {
         std::cout << "Welcome to OpenCV " << CV_VERSION << std::endl;
     }
-
     return 0;
 }

samples/cpp/peopledetect.cpp

@@ -1,177 +1,126 @@
-#include <iostream>
-#include <stdexcept>
+// 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 <opencv2/objdetect.hpp>
 #include <opencv2/highgui.hpp>
 #include <opencv2/imgproc.hpp>
-#include <opencv2/imgcodecs.hpp>
-#include <opencv2/video.hpp>
 #include <opencv2/videoio.hpp>
+#include <iostream>
+#include <iomanip>
 
 using namespace cv;
 using namespace std;
 
-
-const char* keys =
+class Detector
 {
-    "{ help h      |                     | print help message }"
-    "{ image i     |                     | specify input image}"
-    "{ camera c    |                     | enable camera capturing }"
-    "{ video v     | ../data/vtest.avi   | use video as input }"
-    "{ directory d |                     | images directory}"
-};
-
-static void detectAndDraw(const HOGDescriptor &hog, Mat &img)
-{
-    vector<Rect> found, found_filtered;
-    double t = (double) getTickCount();
-    // Run the detector with default parameters. to get a higher hit-rate
-    // (and more false alarms, respectively), decrease the hitThreshold and
-    // groupThreshold (set groupThreshold to 0 to turn off the grouping completely).
-    hog.detectMultiScale(img, found, 0, Size(8,8), Size(32,32), 1.05, 2);
-    t = (double) getTickCount() - t;
-    cout << "detection time = " << (t*1000./cv::getTickFrequency()) << " ms" << endl;
-
-    for(size_t i = 0; i < found.size(); i++ )
+    enum Mode { Default, Daimler } m;
+    HOGDescriptor hog, hog_d;
+public:
+    Detector() : m(Default), hog(), hog_d(Size(48, 96), Size(16, 16), Size(8, 8), Size(8, 8), 9)
     {
-        Rect r = found[i];
-
-        size_t j;
-        // Do not add small detections inside a bigger detection.
-        for ( j = 0; j < found.size(); j++ )
-            if ( j != i && (r & found[j]) == r )
-                break;
-
-        if ( j == found.size() )
-            found_filtered.push_back(r);
+        hog.setSVMDetector(HOGDescriptor::getDefaultPeopleDetector());
+        hog_d.setSVMDetector(HOGDescriptor::getDaimlerPeopleDetector());
     }
-
-    for (size_t i = 0; i < found_filtered.size(); i++)
+    void toggleMode() { m = (m == Default ? Daimler : Default); }
+    string modeName() const { return (m == Default ? "Default" : "Daimler"); }
+    vector<Rect> detect(InputArray img)
+    {
+        // Run the detector with default parameters. to get a higher hit-rate
+        // (and more false alarms, respectively), decrease the hitThreshold and
+        // groupThreshold (set groupThreshold to 0 to turn off the grouping completely).
+        vector<Rect> found;
+        if (m == Default)
+            hog.detectMultiScale(img, found, 0, Size(8,8), Size(32,32), 1.05, 2, false);
+        else if (m == Daimler)
+            hog_d.detectMultiScale(img, found, 0.5, Size(8,8), Size(32,32), 1.05, 2, true);
+        return found;
+    }
+    void adjustRect(Rect & r) const
     {
-        Rect r = found_filtered[i];
-
         // The HOG detector returns slightly larger rectangles than the real objects,
         // so we slightly shrink the rectangles to get a nicer output.
         r.x += cvRound(r.width*0.1);
         r.width = cvRound(r.width*0.8);
         r.y += cvRound(r.height*0.07);
         r.height = cvRound(r.height*0.8);
-        rectangle(img, r.tl(), r.br(), cv::Scalar(0,255,0), 3);
     }
-}
+};
+
+static const string keys = "{ help h   |   | print help message }"
+                           "{ camera c | 0 | capture video from camera (device index starting from 0) }"
+                           "{ video v  |   | use video as input }";
 
 int main(int argc, char** argv)
 {
     CommandLineParser parser(argc, argv, keys);
-
+    parser.about("This sample demonstrates the use ot the HoG descriptor.");
     if (parser.has("help"))
     {
-        cout << "\nThis program demonstrates the use of the HoG descriptor using\n"
-            " HOGDescriptor::hog.setSVMDetector(HOGDescriptor::getDefaultPeopleDetector());\n";
         parser.printMessage();
-        cout << "During execution:\n\tHit q or ESC key to quit.\n"
-            "\tUsing OpenCV version " << CV_VERSION << "\n"
-            "Note: camera device number must be different from -1.\n" << endl;
         return 0;
     }
-
-    HOGDescriptor hog;
-    hog.setSVMDetector(HOGDescriptor::getDefaultPeopleDetector());
-    namedWindow("people detector", 1);
-
-    string pattern_glob = "";
-    string video_filename = "../data/vtest.avi";
-    int camera_id = -1;
-    if (parser.has("directory"))
+    int camera = parser.get<int>("camera");
+    string file = parser.get<string>("video");
+    if (!parser.check())
     {
-        pattern_glob = parser.get<string>("directory");
+        parser.printErrors();
+        return 1;
     }
-    else if (parser.has("image"))
-    {
-        pattern_glob = parser.get<string>("image");
-    }
-    else if (parser.has("camera"))
-    {
-        camera_id = parser.get<int>("camera");
-    }
-    else if (parser.has("video"))
+
+    VideoCapture cap;
+    if (file.empty())
+        cap.open(camera);
+    else
+        cap.open(file.c_str());
+    if (!cap.isOpened())
     {
-        video_filename = parser.get<string>("video");
+        cout << "Can not open video stream: '" << (file.empty() ? "<camera>" : file) << "'" << endl;
+        return 2;
     }
 
-    if (!pattern_glob.empty() || camera_id != -1 || !video_filename.empty())
+    cout << "Press 'q' or <ESC> to quit." << endl;
+    cout << "Press <space> to toggle between Default and Daimler detector" << endl;
+    Detector detector;
+    Mat frame;
+    for (;;)
     {
-        //Read from input image files
-        vector<String> filenames;
-        //Read from video file
-        VideoCapture vc;
-        Mat frame;
-
-        if (!pattern_glob.empty())
+        cap >> frame;
+        if (frame.empty())
         {
-            String folder(pattern_glob);
-            glob(folder, filenames);
+            cout << "Finished reading: empty frame" << endl;
+            break;
         }
-        else if (camera_id != -1)
+        int64 t = getTickCount();
+        vector<Rect> found = detector.detect(frame);
+        t = getTickCount() - t;
+
+        // show the window
         {
-            vc.open(camera_id);
-            if (!vc.isOpened())
-            {
-                stringstream msg;
-                msg << "can't open camera: " << camera_id;
-                throw runtime_error(msg.str());
-            }
+            ostringstream buf;
+            buf << "Mode: " << detector.modeName() << " ||| "
+                << "FPS: " << fixed << setprecision(1) << (getTickFrequency() / (double)t);
+            putText(frame, buf.str(), Point(10, 30), FONT_HERSHEY_PLAIN, 2.0, Scalar(0, 0, 255), 2, LINE_AA);
         }
-        else
+        for (vector<Rect>::iterator i = found.begin(); i != found.end(); ++i)
         {
-            vc.open(video_filename.c_str());
-            if (!vc.isOpened())
-                throw runtime_error(string("can't open video file: " + video_filename));
+            Rect &r = *i;
+            detector.adjustRect(r);
+            rectangle(frame, r.tl(), r.br(), cv::Scalar(0, 255, 0), 2);
         }
+        imshow("People detector", frame);
 
-        vector<String>::const_iterator it_image = filenames.begin();
-
-        for (;;)
+        // interact with user
+        const char key = (char)waitKey(30);
+        if (key == 27 || key == 'q') // ESC
         {
-            if (!pattern_glob.empty())
-            {
-                bool read_image_ok = false;
-                for (; it_image != filenames.end(); ++it_image)
-                {
-                    cout << "\nRead: " << *it_image << endl;
-                    // Read current image
-                    frame = imread(*it_image);
-
-                    if (!frame.empty())
-                    {
-                        ++it_image;
-                        read_image_ok = true;
-                        break;
-                    }
-                }
-
-                //No more valid images
-                if (!read_image_ok)
-                {
-                    //Release the image in order to exit the while loop
-                    frame.release();
-                }
-            }
-            else
-            {
-                vc >> frame;
-            }
-
-            if (frame.empty())
-                break;
-
-            detectAndDraw(hog, frame);
-
-            imshow("people detector", frame);
-            int c = waitKey( vc.isOpened() ? 30 : 0 ) & 255;
-            if ( c == 'q' || c == 'Q' || c == 27)
-                break;
+            cout << "Exit requested" << endl;
+            break;
+        }
+        else if (key == ' ')
+        {
+            detector.toggleMode();
         }
     }
-
     return 0;
 }