//these features are set as the predetected features in last to processing an image
//these features are set as the predetected features in last to processing an image
prc_obj->setLastDetections(features_in);
// at this point we have 0 detections in last, 2 detections in predetected features with different ids, thus we should have 2 new detected features (if max_features set to >= 2)