def METHOD_NAME():
    in_img << imgIn[i, j]
    in_xm1 << xm1
    in_ym1 << ym1
    in_ym2 << ym2
    out_y1 >> y1[i, j]
    out_xm1 >> xm1
    out_ym1 >> ym1
    out_ym2 >> ym2
    out_y1 = a1 * in_img + a2 * in_xm1 + b1 * in_ym1 + b2 * in_ym2
    out_xm1 = in_img
    out_ym2 = in_ym1
    out_ym1 = out_y1