MATLAB tofloat函数

function [out,revertclass] = tofloat(in)
%TOFLOAT Convert image to floating point
%   [OUT REVERTCLASS] = TOFLOAT(IN) converts the input image IN to
%   floating-point. if IN is a double or single image,then OUT 
%   equals IN. Otherwise, OUT equals IM2SINGLE(IN). REVERTCLASS is
%   a function handle that can be used to convert back to the class
%   of IN.
identity = @(x) x;
tosingle = @im2single;

table = {'uint8', tosingle, @im2unit8
    'uint16', tosingle ,@im2unit16
    'int16', tosingle, @im2int16
    'logical', tosingle, @logical
    'double', identity, identity
    'single', identity, identity};

classIndex = find(strcmp(class(in), table(:,1)));

if isempty(classIndex)
   error('Unsupported input image class.');
end

out = table{classIndex, 2}(in);

revertclass = table{classIndex, 3};