Matlab to c code conversion (preparing the matlab code for conversion)

Hi .I want to convert my matlab code to c code.But when i am trying to do do lots of warnings are comping in the code readiness report. Although I have sorted out a lot of issues but still there are some functions which are not supported and i need some alternative.some functions which are not supported I am attaching the full function and its issues.

Please tell me any alternative codesfor the errors.And also pls tell me whther i am checking whter the image is double or not in a correct manner:

    t = isa(Il,'double');%Il=imread("left.png");
if t ==0
    Il = double(Il);
end
t = isa(Ir,'double');%Ir=imread("right.png");
if t ==0
    Ir = double(Ir);
  end

Let me be more specific: these are the lines of the function that are causing some issue-:

    fn = fieldnames(pars); %current parametres fieldnames
main_fn = {'algorithm'};
pm_fn = {'pm_tau','pm_window','pm_keypoints','pm_harris_prctile','pm_searchrange'};
m_fn = {'window','range','tau','epsilon','growing','init_seeds_accept','seeds_accept','searchrange','searchrangeV','max_candidates','vis_step','mu','csbeta','csalgorithm','grow_version'};

Now in this it is saying that code generation only supports cell operations for varargin and vararout

second issue

     *%main parametres*
main_pars = [];
main_fn_ = intersect(fn,main_fn);
for i=1:length(main_fn_);
   *main_pars.(main_fn_(i))=pars.(main_fn_(i));*

      %prematching parametres
 pm_pars = [];
pm_fn_ = intersect(fn,pm_fn);
for i=1:length(pm_fn_);
   *pm_pars.(pm_fn_{i})=pars.(pm_fn_{i});*

      %matching parametres
    m_pars = [];
   m_fn_ = intersect(fn,m_fn);
for i=1:length(m_fn_);
    *m_pars.(m_fn_{i})=pars.(m_fn_{i});*
end

It is showing the same message here also for these lines in the above code:

   *m_pars.(m_fn_{i})=pars.(m_fn_{i});*

   *main_pars.(main_fn_(i))=pars.(main_fn_(i));*

 *pm_pars.(pm_fn_{i})=pars.(pm_fn_{i});*

ALL THE CODE IS GIVEN IN THE FUNCTION ATTACHED BELOW IF POSSIBLE THEN KINDLY DO THE CHANGES IN THE FUNCTION ITSELF OR PLEASE ANSWER BELOW

If u want me to be specific then pls tell that in the comment. Oherwise all the information is provided in the lines and also i have attached the matlab fucntion.