How to save a binary image

I want to save an image with only black and white values, as my image is uint8 the image has only two values, 0 and 255. When I display the image on maltab it is what I wants but when I enter the folder where it is saved it isn't the same image.

A = imread('i000qa-fn.jpg');

for vv = 1: 640

for vr = 1:480

if (A(vv,vr) <= 200)

A(vv,vr) = 0;

else

A(vv,vr) = 255;

end

end

end

imwrite(uint8(A),'/Users/victorjavierper/Documents/MATLAB/IMAGENES CARA/LabeledF/i000qa-fn.jpg');

figure

imshow(A)

The desire image looks like this, shown with imshow.

While the image saved looks like.

[DGM]

Don't use JPG for anything other than visualization -- especially not for binarized images that need to be processed later. If you have images dominated by flat areas of solid color and hard edges, JPG will do nothing but ruin them, all while providing a file size that's larger than better options.

A = imread('cameraman.tif')>130;
imshow(A)

% you could use PNG
imwrite(A,'binary.png')
Bpng = imread('binary.png');
imshow(imfuse(A,Bpng,'diff')) % ZERO ERROR

S = imfinfo('binary.png');
S.FileSize % 3kB for a lossless file

ans = 3070

% or you could use JPG
imwrite(A,'binary.jpg')
Bjpg = imread('binary.jpg');
imshow(imfuse(A,Bjpg,'diff')) % fidelity is garbage

S = imfinfo('binary.jpg');
S.FileSize % you're paying 5.7x as much to ruin your data

ans = 17635

... and yes, error will still exist, no matter what you set the 'quality' parameter to.

Answer 1

[KALYAN ACHARJYA]

imwrite(A,'file_name.tif');

Answer 2

[Johannes Kalliauer]

imwrite(logical(B),'output_binary.png');

% getting example file from internet
rgb = webread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/233522/image.png');
imwrite(rgb,'input.png')

% inizalizing variables
A = imread('input.png');
Dim = size(A);
B = false(Dim(1),Dim(2));

%everything bright should be with and everything else black
for vv = 1: 422
        for vr = 1:311
            if (median([A(vv,vr,1),A(vv,vr,2),A(vv,vr,3)]) <= 200)
                A(vv,vr,1) = 0;
                A(vv,vr,2) = 0;
                A(vv,vr,3) = 0;
            else
                A(vv,vr,1) = 255;
                A(vv,vr,2) = 255;
                A(vv,vr,3) = 255;
                B(vv,vr)=true;
            end
        end
end

% 8-bit-figure
imwrite(uint8(A),'output_8bit.png'); 
figure(5)
imshow(A)

% 1-bit-figure
imwrite(logical(B),'output_binary.png'); 
figure(6)
imshow(B)

A working example would be:

% getting example file from internet

rgb = webread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/233522/image.png');

imwrite(rgb,'input.png')

% inizalizing variables

A = imread('input.png');

Dim = size(A);

B = false(Dim(1),Dim(2));

%everything bright should be with and everything else black

for vv = 1: 422

for vr = 1:311

if (median([A(vv,vr,1),A(vv,vr,2),A(vv,vr,3)]) <= 200)

A(vv,vr,1) = 0;

A(vv,vr,2) = 0;

A(vv,vr,3) = 0;

else

A(vv,vr,1) = 255;

A(vv,vr,2) = 255;

A(vv,vr,3) = 255;

B(vv,vr)=true;

end

end

end

% 8-bit-figure

imwrite(uint8(A),'output_8bit.png');

figure(5)

imshow(A)

% 1-bit-figure

imwrite(logical(B),'output_binary.png');

figure(6)

imshow(B)