Update HOGDescriptor documentation

modules/objdetect/include/opencv2/objdetect.hpp

@@ -352,22 +352,54 @@ struct DetectionROI
    std::vector<double> confidences;
 };
 
-/**@example peopledetect.cpp
+/**@brief Implementation of HOG (Histogram of Oriented Gradients) descriptor and object detector.
+
+the HOG descriptor algorithm introduced by Navneet Dalal and Bill Triggs @cite Dalal2005 .
+
+useful links:
+
+https://hal.inria.fr/inria-00548512/document/
+
+https://en.wikipedia.org/wiki/Histogram_of_oriented_gradients
+
+https://software.intel.com/en-us/ipp-dev-reference-histogram-of-oriented-gradients-hog-descriptor
+
+http://www.learnopencv.com/histogram-of-oriented-gradients
+
+http://www.learnopencv.com/handwritten-digits-classification-an-opencv-c-python-tutorial
+
  */
 struct CV_EXPORTS_W HOGDescriptor
 {
 public:
-    enum { L2Hys = 0
+    enum { L2Hys = 0 //!< Default histogramNormType
          };
-    enum { DEFAULT_NLEVELS = 64
+    enum { DEFAULT_NLEVELS = 64 //!< Default nlevels value.
          };
+    /**@brief Creates the HOG descriptor and detector with default params.
 
+    aqual to HOGDescriptor(Size(64,128), Size(16,16), Size(8,8), Size(8,8), 9, 1 )
+    */
     CV_WRAP HOGDescriptor() : winSize(64,128), blockSize(16,16), blockStride(8,8),
         cellSize(8,8), nbins(9), derivAperture(1), winSigma(-1),
         histogramNormType(HOGDescriptor::L2Hys), L2HysThreshold(0.2), gammaCorrection(true),
         free_coef(-1.f), nlevels(HOGDescriptor::DEFAULT_NLEVELS), signedGradient(false)
     {}
 
+    /** @overload
+    @param _winSize sets winSize with given value.
+    @param _blockSize sets blockSize with given value.
+    @param _blockStride sets blockStride with given value.
+    @param _cellSize sets cellSize with given value.
+    @param _nbins sets nbins with given value.
+    @param _derivAperture sets derivAperture with given value.
+    @param _winSigma sets winSigma with given value.
+    @param _histogramNormType sets histogramNormType with given value.
+    @param _L2HysThreshold sets L2HysThreshold with given value.
+    @param _gammaCorrection sets gammaCorrection with given value.
+    @param _nlevels sets nlevels with given value.
+    @param _signedGradient sets signedGradient with given value.
+    */
     CV_WRAP HOGDescriptor(Size _winSize, Size _blockSize, Size _blockStride,
                   Size _cellSize, int _nbins, int _derivAperture=1, double _winSigma=-1,
                   int _histogramNormType=HOGDescriptor::L2Hys,
@@ -379,97 +411,262 @@ public:
     gammaCorrection(_gammaCorrection), free_coef(-1.f), nlevels(_nlevels), signedGradient(_signedGradient)
     {}
 
+    /** @overload
+    @param filename the file name containing  HOGDescriptor properties and coefficients of the trained classifier
+    */
     CV_WRAP HOGDescriptor(const String& filename)
     {
         load(filename);
     }
 
+    /** @overload
+    @param d the HOGDescriptor which cloned to create a new one.
+    */
     HOGDescriptor(const HOGDescriptor& d)
     {
         d.copyTo(*this);
     }
 
+    /**@brief Default destructor.
+    */
     virtual ~HOGDescriptor() {}
 
+    /**@brief Returns the number of coefficients required for the classification.
+    */
     CV_WRAP size_t getDescriptorSize() const;
+
+    /** @brief Checks if detector size equal to descriptor size.
+    */
     CV_WRAP bool checkDetectorSize() const;
+
+    /** @brief Returns winSigma value
+    */
     CV_WRAP double getWinSigma() const;
 
+    /**@example peopledetect.cpp
+    */
+    /**@brief Sets coefficients for the linear SVM classifier.
+    @param _svmdetector coefficients for the linear SVM classifier.
+    */
     CV_WRAP virtual void setSVMDetector(InputArray _svmdetector);
 
+    /** @brief Reads HOGDescriptor parameters from a file node.
+    @param fn File node
+    */
     virtual bool read(FileNode& fn);
+
+    /** @brief Stores HOGDescriptor parameters in a file storage.
+    @param fs File storage
+    @param objname Object name
+    */
     virtual void write(FileStorage& fs, const String& objname) const;
 
+    /** @brief loads coefficients for the linear SVM classifier from a file
+    @param filename Name of the file to read.
+    @param objname The optional name of the node to read (if empty, the first top-level node will be used).
+    */
     CV_WRAP virtual bool load(const String& filename, const String& objname = String());
+
+    /** @brief saves coefficients for the linear SVM classifier to a file
+    @param filename File name
+    @param objname Object name
+    */
     CV_WRAP virtual void save(const String& filename, const String& objname = String()) const;
+
+    /** @brief clones the HOGDescriptor
+    @param c cloned HOGDescriptor
+    */
     virtual void copyTo(HOGDescriptor& c) const;
 
+    /**@example train_HOG.cpp
+    */
+    /** @brief Computes HOG descriptors of given image.
+    @param img Matrix of the type CV_8U containing an image where HOG features will be calculated.
+    @param descriptors Matrix of the type CV_32F
+    @param winStride Window stride. It must be a multiple of block stride.
+    @param padding Padding
+    @param locations Vector of Point
+    */
     CV_WRAP virtual void compute(InputArray img,
                          CV_OUT std::vector<float>& descriptors,
                          Size winStride = Size(), Size padding = Size(),
                          const std::vector<Point>& locations = std::vector<Point>()) const;
 
-    //! with found weights output
+    /** @brief Performs object detection without a multi-scale window.
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param foundLocations Vector of point where each point contains left-top corner point of detected object boundaries.
+    @param weights Vector that will contain confidence values for each detected object.
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane.
+    Usually it is 0 and should be specfied in the detector coefficients (as the last free coefficient).
+    But if the free coefficient is omitted (which is allowed), you can specify it manually here.
+    @param winStride Window stride. It must be a multiple of block stride.
+    @param padding Padding
+    @param searchLocations Vector of Point includes set of requrested locations to be evaluated.
+    */
     CV_WRAP virtual void detect(const Mat& img, CV_OUT std::vector<Point>& foundLocations,
                         CV_OUT std::vector<double>& weights,
                         double hitThreshold = 0, Size winStride = Size(),
                         Size padding = Size(),
                         const std::vector<Point>& searchLocations = std::vector<Point>()) const;
-    //! without found weights output
+
+    /** @brief Performs object detection without a multi-scale window.
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param foundLocations Vector of point where each point contains left-top corner point of detected object boundaries.
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane.
+    Usually it is 0 and should be specfied in the detector coefficients (as the last free coefficient).
+    But if the free coefficient is omitted (which is allowed), you can specify it manually here.
+    @param winStride Window stride. It must be a multiple of block stride.
+    @param padding Padding
+    @param searchLocations Vector of Point includes locations to search.
+    */
     virtual void detect(const Mat& img, CV_OUT std::vector<Point>& foundLocations,
                         double hitThreshold = 0, Size winStride = Size(),
                         Size padding = Size(),
                         const std::vector<Point>& searchLocations=std::vector<Point>()) const;
 
-    //! with result weights output
+    /** @brief Detects objects of different sizes in the input image. The detected objects are returned as a list
+    of rectangles.
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param foundLocations Vector of rectangles where each rectangle contains the detected object.
+    @param foundWeights Vector that will contain confidence values for each detected object.
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane.
+    Usually it is 0 and should be specfied in the detector coefficients (as the last free coefficient).
+    But if the free coefficient is omitted (which is allowed), you can specify it manually here.
+    @param winStride Window stride. It must be a multiple of block stride.
+    @param padding Padding
+    @param scale Coefficient of the detection window increase.
+    @param finalThreshold Final threshold
+    @param useMeanshiftGrouping indicates grouping algorithm
+    */
     CV_WRAP virtual void detectMultiScale(InputArray img, CV_OUT std::vector<Rect>& foundLocations,
                                   CV_OUT std::vector<double>& foundWeights, double hitThreshold = 0,
                                   Size winStride = Size(), Size padding = Size(), double scale = 1.05,
                                   double finalThreshold = 2.0,bool useMeanshiftGrouping = false) const;
-    //! without found weights output
+
+    /** @brief Detects objects of different sizes in the input image. The detected objects are returned as a list
+    of rectangles.
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param foundLocations Vector of rectangles where each rectangle contains the detected object.
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane.
+    Usually it is 0 and should be specfied in the detector coefficients (as the last free coefficient).
+    But if the free coefficient is omitted (which is allowed), you can specify it manually here.
+    @param winStride Window stride. It must be a multiple of block stride.
+    @param padding Padding
+    @param scale Coefficient of the detection window increase.
+    @param finalThreshold Final threshold
+    @param useMeanshiftGrouping indicates grouping algorithm
+    */
     virtual void detectMultiScale(InputArray img, CV_OUT std::vector<Rect>& foundLocations,
                                   double hitThreshold = 0, Size winStride = Size(),
                                   Size padding = Size(), double scale = 1.05,
                                   double finalThreshold = 2.0, bool useMeanshiftGrouping = false) const;
 
+    /** @brief  Computes gradients and quantized gradient orientations.
+    @param img Matrix contains the image to be computed
+    @param grad Matrix of type CV_32FC2 contains computed gradients
+    @param angleOfs Matrix of type CV_8UC2 contains quantized gradient orientations
+    @param paddingTL Padding from top-left
+    @param paddingBR Padding from bottom-right
+    */
     CV_WRAP virtual void computeGradient(const Mat& img, CV_OUT Mat& grad, CV_OUT Mat& angleOfs,
                                  Size paddingTL = Size(), Size paddingBR = Size()) const;
 
+    /** @brief Returns coefficients of the classifier trained for people detection (for 64x128 windows).
+    */
     CV_WRAP static std::vector<float> getDefaultPeopleDetector();
+
+    /**@example hog.cpp
+    */
+    /** @brief Returns coefficients of the classifier trained for people detection (for 48x96 windows).
+    */
     CV_WRAP static std::vector<float> getDaimlerPeopleDetector();
 
+    //! Detection window size. Align to block size and block stride. Default value is Size(64,128).
     CV_PROP Size winSize;
+
+    //! Block size in pixels. Align to cell size. Default value is Size(16,16).
     CV_PROP Size blockSize;
+
+    //! Block stride. It must be a multiple of cell size. Default value is Size(8,8).
     CV_PROP Size blockStride;
+
+    //! Cell size. Default value is Size(8,8).
     CV_PROP Size cellSize;
+
+    //! Number of bins used in the calculation of histogram of gradients. Default value is 9.
     CV_PROP int nbins;
+
+    //! not documented
     CV_PROP int derivAperture;
+
+    //! Gaussian smoothing window parameter.
     CV_PROP double winSigma;
+
+    //! histogramNormType
     CV_PROP int histogramNormType;
+
+    //! L2-Hys normalization method shrinkage.
     CV_PROP double L2HysThreshold;
+
+    //! Flag to specify whether the gamma correction preprocessing is required or not.
     CV_PROP bool gammaCorrection;
+
+    //! coefficients for the linear SVM classifier.
     CV_PROP std::vector<float> svmDetector;
+
+    //! coefficients for the linear SVM classifier used when OpenCL is enabled
     UMat oclSvmDetector;
+
+    //! not documented
     float free_coef;
+
+    //! Maximum number of detection window increases. Default value is 64
     CV_PROP int nlevels;
+
+    //! Indicates signed gradient will be used or not
     CV_PROP bool signedGradient;
 
-
+    /** @brief evaluate specified ROI and return confidence value for each location
-    //! evaluate specified ROI and return confidence value for each location
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param locations Vector of Point
+    @param foundLocations Vector of Point where each Point is detected object's top-left point.
+    @param confidences confidences
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane. Usually
+    it is 0 and should be specfied in the detector coefficients (as the last free coefficient). But if
+    the free coefficient is omitted (which is allowed), you can specify it manually here
+    @param winStride winStride
+    @param padding padding
+    */
     virtual void detectROI(const cv::Mat& img, const std::vector<cv::Point> &locations,
                                    CV_OUT std::vector<cv::Point>& foundLocations, CV_OUT std::vector<double>& confidences,
                                    double hitThreshold = 0, cv::Size winStride = Size(),
                                    cv::Size padding = Size()) const;
 
-    //! evaluate specified ROI and return confidence value for each location in multiple scales
+    /** @brief evaluate specified ROI and return confidence value for each location in multiple scales
+    @param img Matrix of the type CV_8U or CV_8UC3 containing an image where objects are detected.
+    @param foundLocations Vector of rectangles where each rectangle contains the detected object.
+    @param locations Vector of DetectionROI
+    @param hitThreshold Threshold for the distance between features and SVM classifying plane. Usually it is 0 and should be specfied
+    in the detector coefficients (as the last free coefficient). But if the free coefficient is omitted (which is allowed), you can specify it manually here.
+    @param groupThreshold Minimum possible number of rectangles minus 1. The threshold is used in a group of rectangles to retain it.
+    */
     virtual void detectMultiScaleROI(const cv::Mat& img,
                                      CV_OUT std::vector<cv::Rect>& foundLocations,
                                      std::vector<DetectionROI>& locations,
                                      double hitThreshold = 0,
                                      int groupThreshold = 0) const;
 
-    //! read/parse Dalal's alt model file
+    /** @brief read/parse Dalal's alt model file
+    @param modelfile Path of Dalal's alt model file.
+    */
     void readALTModel(String modelfile);
+
+    /** @brief Groups the object candidate rectangles.
+    @param rectList  Input/output vector of rectangles. Output vector includes retained and grouped rectangles. (The Python list is not modified in place.)
+    @param weights Input/output vector of weights of rectangles. Output vector includes weights of retained and grouped rectangles. (The Python list is not modified in place.)
+    @param groupThreshold Minimum possible number of rectangles minus 1. The threshold is used in a group of rectangles to retain it.
+    @param eps Relative difference between sides of the rectangles to merge them into a group.
+    */
     void groupRectangles(std::vector<cv::Rect>& rectList, std::vector<double>& weights, int groupThreshold, double eps) const;
 };