HoGIntegralImage.h

#ifndef HOG_INTEGRAL_IMAGE_HEADER
#define HOG_INTEGRAL_IMAGE_HEADER

#define NUM_HOG_BINS 9

#include "IntegralImage.h"

class HoGIntegralImage : public IntegralImage {
public:
    // img should be CV_8UC1.
    HoGIntegralImage(const cv::Mat &img);
    HoGIntegralImage(int w, int h);
    ~HoGIntegralImage();

    // Calculate the integral image.
    // Should be called if the img changed.
    virtual void CalculateInt(const cv::Mat &img);

    virtual void Dump(const char *filename) const;

    virtual void GetSum(const Rect &roi, float *result) const;

private:
    // Data.
    float *intImage;

    // Step.
    int m_step;

    static const float xVector[9];
    static const float yVector[9];

    // Some helper function.
    inline int Direct(float x, float y) {
        float max = 0.0;
        int ret = 0;

        // Try to avoid float problem.
        if (y == 0.0f)
            y = 0.01f;
        for (int i = 0; i < 9; i++) {
            float proj = fabsf(x * xVector[i] + y * yVector[i]);
            if (proj > max) {
                max = proj;
                ret = i;
            }
        }
        return ret;
    }
};

#endif