how to make this code make the output as an image?

this code is supposed to import image (dice) then make edits on it using the 2 for loops i added. everything works fine and the image is imported correctly but the output (out) is shown as a matrix not as a black and white image which is what i want.

function out = rec7a2(in1,in2)
in2 = 100;
in1 = imread('dice.jpeg') % a unit8 image input
in1 = im2gray(in1);  %change it to black and white
for i = 1:size(in1,1)
    for j = 1:size(in1,2)
        if in1(i,j) >= in2 
            out(i,j) = 255 - in2;
        else
            out(i,j) = in2;
        end
    end
end
end

Answer 1

[Walter Roberson]

out(i,j) = 255 - in2;

You are building up a numeric array, and that numeric array is your output variable.

MATLAB does not have any way to store "black and white image" as such. Unless you were to design your own object class, MATLAB cannot do something like:

outimg = rec7a2('flamingos.jpg', 'foggy.png');

to have outimg be an "image" that would show up in graphic form if you were to

disp(outimg)

What MATLAB does have is numeric arrays that can be interpreted as images, and MATLAB has graphics objects that give information about image arrays already drawn on the screen as images.

You could change your code so that it was something like

function outimg = rec7a2(in1,in2)
  %then your math stuff
  outimg = image(out);
  colormap(outimg.Parent, gray(256));
end

That would then return a handle to the graphics object that has displayed the array out as a black and white image. But you would not then be able to process the array of data further -- not unless you fetched it from the graphics handle.

Side note: you really shouldn't ignore your input variables in1 and in2 . If you are going to hard-code those in your function, then there is no point in accepting inputs.

[Mohamed Arafa]

thank you that really helped but what did you mean with your side note ?

[Walter Roberson]

function out = rec7a2(in1,in2)
in2 = 100;
in1 = imread('dice.jpeg') % a unit8 image input

Do not do that. Instead create test7a2.m

in2 = 100;
in1 = imread('dice.jpeg') % a unit8 image input
out = rec7a2(in1, in2) ;

and

function out = rec7a2(in1,in2)
% in1 should be image array 
% in2 should be numeric threshold

without assigning to in1 or in2 inside the function

Answer 2

[Milton]

Quero todo código completo. Output, erosão, dilação entre outros

[Walter Roberson]

Approximate translation:

I want all the complete code. Output, erosion, dilation among others