An imaging-assisted angular calibration method comprises receiving an image of a spatial resolution chart on a flat board, the image taken by a camera positioned at a predetermined distance from the spatial resolution chart; determining an angular resolution of the camera based on the image of the spatial resolution chart and the predetermined distance; and receiving an image of laser spots in a raster scan pattern incident on the flat board, the laser spots emitted from a LiDAR device positioned at the predetermined distance from the flat board, the raster scan pattern generated based on a group of preset values in the LiDAR device. A set of stepwise moving angles of the LiDAR device corresponding to the group of preset values are then calculated based on the image of the laser spots and the angular resolution of the camera for use in calibrating the LiDAR device.