Function getFeatureMaps

src/Tracker/ldes/fhog.cpp:80–249

// Getting feature map for the selected subimage // // API // int getFeatureMaps(const cv::Mat& image, const int k, featureMap **map); // INPUT // image - selected subimage // k - size of cells // OUTPUT // map - feature map // RESULT // Error status */

// Error status
*/
int getFeatureMaps(const cv::Mat& image, const int k, CvLSVMFeatureMapCaskade **map)
{
    float kernel[3] = {-1.f, 0.f, 1.f};
    cv::Mat kernel_dx(1, 3, CV_32F, kernel);
    cv::Mat kernel_dy(3, 1, CV_32F, kernel);

    float boundary_x[NUM_SECTOR + 1];
    float boundary_y[NUM_SECTOR + 1];

    int height = image.rows;
    int width  = image.cols;

    int numChannels = image.channels();

    int sizeX = width  / k;
    int sizeY = height / k;
    int px    = 3 * NUM_SECTOR; 
    int p     = px;
    int stringSize = sizeX * p;
    allocFeatureMapObject(map, sizeX, sizeY, p);

	cv::Mat dx;
	cv::Mat dy;
	cv::filter2D(image, dx, CV_32FC3, kernel_dx, cv::Point(-1, 0));
	cv::filter2D(image, dy, CV_32FC3, kernel_dy, cv::Point(0, -1));
    
    for (int i = 0; i <= NUM_SECTOR; i++)
    {
        float arg_vector    = ( (float) i ) * ( (float)(PI) / (float)(NUM_SECTOR) );
        boundary_x[i] = cosf(arg_vector);
        boundary_y[i] = sinf(arg_vector);
    }/*for(i = 0; i <= NUM_SECTOR; i++) */

    float* r  = (float *)malloc( sizeof(float) * (width * height));
    int* alfa = (int   *)malloc( sizeof(int  ) * (width * height * 2));

    for (int j = 1; j < height - 1; j++)
    {
        const float* datadx = dx.ptr<float>(j);
		const float* datady = dy.ptr<float>(j);
        for (int i = 1; i < width - 1; i++)
        {
            int c = 0;
            float x = (datadx[i * numChannels + c]);
            float y = (datady[i * numChannels + c]);

            r[j * width + i] =sqrtf(x * x + y * y);
            for(int ch = 1; ch < numChannels; ch++)
            {
                float tx = (datadx[i * numChannels + ch]);
                float ty = (datady[i * numChannels + ch]);
                float magnitude = sqrtf(tx * tx + ty * ty);
                if(magnitude > r[j * width + i])
                {
                    r[j * width + i] = magnitude;
                    c = ch;
                    x = tx;
                    y = ty;