A method and server for training a machine-learning algorithm (MLA) to detect objects in sensor data acquired by a second sensor mounted on a second vehicle located at a second distance from the objects, the MLA having been trained to detect the objects in sensor data acquired by a first sensor mounted on a first vehicle located at a first distance from the objects. First sensor data acquired by the first sensor on the first vehicle is aligned with second sensor data acquired by the second sensor on the second vehicle. The MLA determines objects and objects classes in the aligned first sensor data. The object classes in the aligned first sensor data are assigned to corresponding portions in the aligned second sensor data. The MLA is trained on the labelled portions in the aligned second sensor data to recognize and classify objects at the second distance.