Calibration target(s) are mounted on a vehicle including a plurality of cameras. The calibration targets are in the field of view of the cameras. The calibration targets are sometimes LED or IR illumined targets. The targets in some embodiments are shielded to block light from oncoming cars and/or to block driver view of the target to reduce the risk of driver distraction. The cameras capture images at the same time. Calibration operations are then performed using the target or targets included in the captured images as a known visual reference of a known shape. size and/or having a known image pattern. Calibration parameters including parameters providing information about the location and/or spatial positions of the cameras with respect to each other and/or the target are generated from the captured images. Distance to objects in the environment which are included in the captured images are then determined.