aux_get_dummy_resp.m

Standard model object recognition matlab code

function [r all_size] = aux_get_dummy_resp (layer,stim_size,all_oper,varargin)

% FUNCTION [r all_size] = aux_get_dummy_resp (layer)
%
% Based on the information given in init_filter_def and stim_size,
% calculate the size of a given layer, which will depend on the
% size of the previous layers.  Return a dummy structure r with the
% correct size.
%
% If the 3-d matrix is wanted (instead of 2-d), set the number of
% features in varargin{1} = 0.
% If the response before mixing scale is needed, set varargin{2} = 0.

if size(stim_size,1) ~= 2
  stim_size = stim_size';
end

[a,b,c,d] = init_filter_def(1);
num_scale_l0 = a;
% all_size will keep track of all sizes at different layers, in 2
% (x and y) by number of scales matrices.
all_size = [];
all_size = setfield(all_size, 'Layer0', ...
    repmat(stim_size,[1,num_scale_l0]));

for i = 1:layer
   if i~=5
      prev_size = getfield(all_size,['Layer' num2str(i-1)]);
   else
      % for C2 layer
      prev_size = getfield(all_size,'Layer2');      
   end

  % Get the definition of filters.
  [a,b,c,d] = init_filter_def(i);
  f_size  = b(1:2,:); % filter sizes.
  shifts = c; % shift of convolution window.
  m = d; % see filt_scalemixing.m.

  next_size = zeros(2,a); % x and y dimensions x num scale.
  next_size_new = zeros(2,max(m)); % x and y dimensions x num scale.

  for s = 1:a % loop thru scales
    % For some operations, the prev layer is cropped or
    % zero-padded.
    x = zeros(prev_size(1,s),prev_size(2,s));
    x = comp_crop_or_zeropad(x,f_size(:,s),c(s),all_oper(i,:));
    next_size(:,s) = (size(x)'-f_size(:,s))/c(s) + 1;
    if (next_size(:,s)-floor(next_size(:,s)))~=0
      error('Border crop/pad did not work well.');
    end
  end
  
  % Now becase of scale mixing, not all next_siz will be available
  % for the next size.  See filt_scalemixing.m

  for m_idx = 1:max(m)
    which_scale = find(m==m_idx);
    next_size_new(:,m_idx) = max(next_size(:,which_scale),[],2);
  end

  all_size = setfield(all_size,['Layer' num2str(i)],next_size_new);
end

% Now prepare the dummy response.
if length(varargin)>0
  num_feature = varargin{1};
  if length(varargin)>1
    % Response before mixing scale is wanted.
    next_size_new = next_size;
  else
    % Mix the scale.
  end
else
  num_feature = 1;
end

r = [];
for s = 1:size(next_size_new,2)
  r_tmp = zeros(next_size_new(1,s),next_size_new(2,s),num_feature);
  r = setfield(r,['s' num2str(s)],r_tmp);
end