OpenCV中的 HOGDescriptor 類

其定義在 object.hpp中找到的：

struct CV_EXPORTS_W HOGDescriptor
{
public:
enum { L2Hys=0 };
enum { DEFAULT_NLEVELS=64 };

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),
nlevels(HOGDescriptor::DEFAULT_NLEVELS)
{}

CV_WRAP HOGDescriptor(Size _winSize, Size _blockSize, Size _blockStride,
Size _cellSize, int _nbins, int _derivAperture=1, double _winSigma=-1,
int _histogramNormType=HOGDescriptor::L2Hys,
double _L2HysThreshold=0.2, bool _gammaCorrection=false,
int _nlevels=HOGDescriptor::DEFAULT_NLEVELS)
: winSize(_winSize), blockSize(_blockSize), blockStride(_blockStride), cellSize(_cellSize),
nbins(_nbins), derivAperture(_derivAperture), winSigma(_winSigma),
histogramNormType(_histogramNormType), L2HysThreshold(_L2HysThreshold),
gammaCorrection(_gammaCorrection), nlevels(_nlevels)
{}

CV_WRAP HOGDescriptor(const String& filename)
{
load(filename);
}

HOGDescriptor(const HOGDescriptor& d)
{
d.copyTo(*this);
}

virtual ~HOGDescriptor() {}

CV_WRAP size_t getDescriptorSize() const;
CV_WRAP bool checkDetectorSize() const;
CV_WRAP double getWinSigma() const;

CV_WRAP virtual void setSVMDetector(InputArray _svmdetector);

virtual bool read(FileNode& fn);
virtual void write(FileStorage& fs, const String& objname) const;

CV_WRAP virtual bool load(const String& filename, const String& objname=String());
CV_WRAP virtual void save(const String& filename, const String& objname=String()) const;
virtual void copyTo(HOGDescriptor& c) const;

CV_WRAP virtual void compute(const Mat& img,
CV_OUT vector<float>& descriptors,
Size winStride=Size(), Size padding=Size(),
const vector<Point>& locations=vector<Point>()) const;
//with found weights output
CV_WRAP virtual void detect(const Mat& img, CV_OUT vector<Point>& foundLocations,
CV_OUT vector<double>& weights,
double hitThreshold=0, Size winStride=Size(),
Size padding=Size(),
const vector<Point>& searchLocations=vector<Point>()) const;
//without found weights output
virtual void detect(const Mat& img, CV_OUT vector<Point>& foundLocations,
double hitThreshold=0, Size winStride=Size(),
Size padding=Size(),
const vector<Point>& searchLocations=vector<Point>()) const;
//with result weights output
CV_WRAP virtual void detectMultiScale(const Mat& img, CV_OUT vector<Rect>& foundLocations,
CV_OUT 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
virtual void detectMultiScale(const Mat& img, CV_OUT vector<Rect>& foundLocations,
double hitThreshold=0, Size winStride=Size(),
Size padding=Size(), double scale=1.05,
double finalThreshold=2.0, bool useMeanshiftGrouping = false) const;

CV_WRAP virtual void computeGradient(const Mat& img, CV_OUT Mat& grad, CV_OUT Mat& angleOfs,
Size paddingTL=Size(), Size paddingBR=Size()) const;

CV_WRAP static vector<float> getDefaultPeopleDetector();
CV_WRAP static vector<float> getDaimlerPeopleDetector();

CV_PROP Size winSize;
CV_PROP Size blockSize;
CV_PROP Size blockStride;
CV_PROP Size cellSize;
CV_PROP int nbins;
CV_PROP int derivAperture;
CV_PROP double winSigma;
CV_PROP int histogramNormType;
CV_PROP double L2HysThreshold;
CV_PROP bool gammaCorrection;
CV_PROP vector<float> svmDetector;
CV_PROP int nlevels;

// evaluate specified ROI and return confidence value for each location
void detectROI(const cv::Mat& img, const 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
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
void readALTModel(std::string modelfile);
};

默認構造函數的幾個參數：

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),
nlevels(HOGDescriptor::DEFAULT_NLEVELS)

winSize ： 窗口的大小
blockSize ：塊的大小
cellSize： 胞元的大小
nbins： 方向bin的個數 nBins表示在一個胞元（cell）中統計梯度的方向數目，例如nBins=9時，在一個胞元內統計9個方向的梯度直方圖，每個方向為360/9=40度。

更詳細請移步： http://www.linuxidc.com/Linux/2014-11/109146.htm

更多詳情見請繼續閱讀下一頁的精彩內容： http://www.linuxidc.com/Linux/2014-11/109157p2.htm

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