What do “mod_scale” and “mod images” in “generate_bicubic_img.m” mean? What is the difference from the input image?

[Yzs007]

function generate_bicubic_img()
%% matlab code to genetate mod images, bicubic-downsampled images and
%% bicubic_upsampled images

%% set configurations
% comment the unnecessary lines
input_folder = '../../datasets/Set5/original';
save_mod_folder = '../../datasets/Set5/GTmod12';
save_lr_folder = '../../datasets/Set5/LRbicx2';
% save_bic_folder = '';

mod_scale = 12;
up_scale = 2;