PatchDataset2(cv::Size patchsize, const std::string &positiveImageListFilename="", const std::string &positiveImageLabelsFilename="", const std::string &negativeImageListFilename="", int posExamplePatchRadius=0, int posExampleScaleRadius=0, int numPosPatches=-1, int numNegPatches=-1, int useFastPatchList=1, double scale=1.)