1)back focus,象方焦点2)image space foral length,象方焦距3)focus in object space,物方焦点4)focus in image space,像方焦点5)quardrantal points,象限方位点6)the curve equation of focus,焦点曲线方程
用法和例句
Through studying two pairs of opposite vertices in tetragon, the author derived the curve equation of focus in form of complex number and its expression of right angle coordinate.