1. An image conversion method, for converting a captured input image in a first view angle coordinate system to an output image in a second view angle coordinate system, the method comprising: capturing an image of a calibration reference pattern comprising: a first calibration reference sub-pattern, comprising a first characteristic pattern group, at least one straight line and a plurality of first grid lines, the first characteristic pattern group having at least two identical first characteristic patterns; and a second calibration reference sub-pattern, comprising a second characteristic pattern group and a second straight line, the second characteristic pattern group having at least two identical second characteristic patterns, wherein the first characteristic patterns of the first characteristic pattern group are equidistant from a border of the first calibration reference sub-pattern, and the second characteristic patterns of the second characteristic pattern group are equidistant from a border of the second calibration reference sub-pattern; identifying the first characteristic patterns and the second characteristic patterns of the calibration reference pattern; obtaining coordinates of the first characteristic patterns and the second characteristic patterns in the first view angle coordinate system and coordinates of the first characteristic patterns and the second characteristic patterns in the second view angle coordinate system, to obtain a coordinate conversion relationship between the first view angle coordinate system and the second view angle coordinate system; and converting the input image to the output image according to the coordinate conversion relationship.