johansson_gavel_subm - construct a Johansson Gavel subharmonic method.
construct a Johansson Gavel subharmonic method. it is described by Johansson and Gavel 1994
subm=johansson_gavel_subm(3);
Chen jingyuan, IAPCM, China.
null_subm , general_subm , lane_subm , quad_pix_subm ,