All result is integer instead double

Question

Dani D 2016-4-25

0
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https://ww2.mathworks.cn/matlabcentral/answers/280895-all-result-is-integer-instead-double

回答： Walter Roberson 2016-4-25

Hello, Why all result after divide isn't double? Just zero or one :( Thanks

input = imread('cameraman.tif');
B = 2;
L = 256;
[m , n] = size(input);
output = zeros(m,n);
output = double(output);
min = min(input(:));
max = max(input(:));
for i = 1 : m 
    for j = 1 : n
         Xmn = double(input(i,j));
        output(i,j) = (Xmn - min )/(max - min);
    end
end

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John D'Errico 2016-4-25

在 MATLAB Online 中打开

It is a REALLY, REALLY, REALLY bad idea to write lines like this:

min = min(input(:));
max = max(input(:));

Note that once you do that, the functions min and max will no longer work properly! So the second time you try to run that code, it will now fail.

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Answer 1

Walter Roberson 2016-4-25

0
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https://ww2.mathworks.cn/matlabcentral/answers/280895-all-result-is-integer-instead-double#answer_219350

The variables you name "min" and "max" are the same data type as your input. If your input is uint8 then min and max are uint8. When you do an operation involving double and uint8, the result is always uint8.