Before revision:  However, many existing classifiers, especially deep neural network classifiers, tend not to be calibrated . Post-hoc calibration is a technique to recalibrate a model , and its goal is to learn a calibration map.
After revision:  However, many existing classifiers, especially deep neural network classifiers, tend not to be calibrated . Post-hoc calibration is a technique to recalibrate a model by learning a calibration map.