matlab adaptthres​h函数源码，149行​cvt2double​是什么意思。

大家好，我最近在学习adaptthresh函数，查看了该函数的源码，其中第149行是I = cvt2double(I);，我感觉这句是数据类型转换成双精度，他的注释也差不多是这样，但是在matlab里没查到这个函数，查了很多资料也没找到cvt2double函数的解释，请问大家有知道的吗。下面是其中一段，这里是21行。完整的大家可以open adaptthresh查看。图像转换成双精度类型的函数我只知道im2double.

function T = adaptthresh(I,varargin)


args = matlab.images.internal.stringToChar(varargin);
matlab.images.internal.errorIfgpuArray(I, varargin{:});

[I,options] = parseInputs(I, args{:});
nhoodSize   = options.NeighborhoodSize;
statistic   = options.Statistic;
isFGBright  = strcmp(options.ForegroundPolarity,'bright');
sensitivity = options.Sensitivity;

if isempty(I)
    T = zeros(size(I));
    return;
end

scaleFactor = sensitivityToScaleFactor(sensitivity,isFGBright);

% Convert image to double-precision. This scales integer data to [0,1].
I = cvt2double(I);

switch statistic
    case 'mean'
        T = localMeanThresh(I,nhoodSize,scaleFactor);
    case 'median'
        T = localMedianThresh(I,nhoodSize,scaleFactor);
    case 'gaussian'
        T = localGaussThresh(I,nhoodSize,scaleFactor);
    otherwise
        assert(false,'Unknown statistic string.')
end

% Restrict T to [0,1]. Saturate output values to lie in [0,1] data range
% for double-precision images.
T = max(min(T,1),0);
end

Answer 1

[ybnubje]

源代码里面这个函数是自己定义的。。。。225行，这东西你右键打开函数就知道了

function I = cvt2double(I)

% im2double is not supported for all classes. This function does the

% conversion for other classes too.

switch class(I)

case {'uint8','uint16','int16','single','double'}

I = im2double(I);

case 'int8'

I = (double(I) + 128) / 255;

case 'uint32'

I = double(I) / 4294967295;

case 'int32'

I = (double(I) + 2147483648) / 4294967295;

otherwise

assert(false,'Incorrect class');

end

end