function g=gscale(f,varargin)

% GSACLE函式實現對輸入影象的標度

% G = GSACLE(F, "full8")將影象標度到[0, 255]全範圍，預設值

% G = GSACLE(F, "full16")將影象標度到[0, 65535]全範圍

% G = GSACLE(F, "minmax", Low, High)將影象標度到[Low, High]全範圍，注意，Low，High

% 的範圍為[0, 1],具體範圍由輸入決定，即輸入輸出的class一致。

% 如果輸入影象是double類，並且值不在[0, 1]的範圍內，那麼在標度之前要進行轉換

if isempty(varargin) % 對程式碼進行最佳化，該語句比 if length(varargin) == 0 快

method="full8"; % 採用預設值

else

method=varargin{1};

end

% 預處理

if strcmp(class(f),"double")&(max(f(:))>1 | min(f(:))<0)

f=mat2gray(f);

end

% 實現標度

switch method

case "full8"

g=im2uint8(mat2gray(double(f)));

case "full16"

g=im2uint16(mat2gray(double(f)));

case "minmax"

low = varargin{2};high = varargin{3};

if low>1 | low<0 |high>1 | high<0 % 判斷引數是否合法

error("Parameters low and high must be in the range [0,1]")

end

if strcmp(class(f),"double")

low_in=min(f(:));

high_in=max(f(:));

elseif strcmp(class(f),"uint8")

low_in=double(min(f(:)))./255;

high_in=double(max(f(:)))./255;

elseif strcmp(class(f),"uint16")

low_in=double(min(f(:)))./65535;

high_in=double(max(f(:)))./65535;

end

g=imadjust(f,[low_in high_in],[low high]);

otherwise

error("Unknown method")

end