void cvCalcProbDensity(CvHistogram* hist1, CvHistogram* hist2, CvHistogram* dst_hist, double scale) {
    void *fptr;

    fptr = dlsym(_Chcv_handle, "cvCalcProbDensity_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return;
    }
    dlrunfun(fptr, NULL, cvCalcProbDensity, hist1, hist2, dst_hist, scale);
}
