utilities（matlab）—— visualizes filters（可视化滤波器）

function [h, array] = display_network(A, opt_normalize, opt_graycolor, cols, opt_colmajor)
% This function visualizes filters in matrix A. Each column of A is a
% filter. We will reshape each column into a square image and visualizes
% on each cell of the visualization panel.
% All other parameters are optional, usually you do not need to worry
% about it.
% opt_normalize: whether we need to normalize the filter so that all of
% them can have similar contrast. Default value is true.
% opt_graycolor: whether we use gray as the heat map. Default is true.
% cols: how many columns are there in the display. Default value is the
% squareroot of the number of columns in A.
% opt_colmajor: you can switch convention to row major for A. In that
% case, each row of A is a filter. Default value is false.
warning off all

if ~exist('opt_normalize', 'var') || isempty(opt_normalize)
opt_normalize= true;
end

if ~exist('opt_graycolor', 'var') || isempty(opt_graycolor)
opt_graycolor= true;
end

if ~exist('opt_colmajor', 'var') || isempty(opt_colmajor)
opt_colmajor = false;
end

display(opt_normalize)

% rescale
A = A - mean(A(:));

if opt_graycolor, colormap(gray); end

% compute rows, cols
[L, M]=size(A);
sz=sqrt(L);
buf=1;
if ~exist('cols', 'var')
if floor(sqrt(M))^2 ~= M
n=ceil(sqrt(M));
while mod(M, n)~=0 && n<1.2*sqrt(M), n=n+1; end
m=ceil(M/n);
else
n=sqrt(M);
m=n;
end
else
n = cols;
m = ceil(M/n);
end

array=-ones(buf+m*(sz+buf),buf+n*(sz+buf));

if ~opt_graycolor
array = 0.1.* array;
end

if ~opt_colmajor
k=1;
for i=1:m
for j=1:n
if k>M,
continue;
end
clim=max(abs(A(:,k)));
if opt_normalize
array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/clim;
else
array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/max(abs(A(:)));
end
k=k+1;
end
end
else
k=1;
for j=1:n
for i=1:m
if k>M,
continue;
end
clim=max(abs(A(:,k)));
if opt_normalize
array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/clim;
else
array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz);
end
k=k+1;
end
end
end

if opt_graycolor
h=imagesc(array,'EraseMode','none',[-1 1]);
else
h=imagesc(array,'EraseMode','none',[-1 1]);
end
axis image off

drawnow;

warning on all