How do I return a matrix from a function?

Hello,

I am trying to write a very simple function that takes as an input an image in .tif format and returns a matrix of doubles where each value corresponds to the value of the pixel in that location of the image.

function A = readMyPicture (fileName)

arguments

fileName % This should be a string, the name of the image you want to read

end

A= double(imread(fileName)); % Converts image to matrix of doubles

end

This seems easy enough, however when I invoke the function (which is defined as a method of a handle class, but anyway I never had problems with other methods such as this one), it tells me the following error (the error appears in red in reality):

A = readMyPicture("example1.tif");

Check for missing argument or incorrect argument data type in call to function'readMyPicture'.

What am I doing wrong? I am very confused.

Thank you!

[Michael Van de Graaff]

You code works for me just fine.

[Dave B]

This code works, could it be that you have a previous version of readMyPicture on the path? Try calling:

which readMyPicture

to make sure you're pointing to the right one?

Or, just in case MATLAB is looking at an old cached copy of readMyPicture (shouldn't be the case, but worth a shot):

clear functions

(or just restart MATLAB)

Demo that what you have works (I cleaned up the spacing, but that was just me being obsessive, what you have is functional):

A = readMyPicture("peppers.png");
imshow(A./255)

function A = readMyPicture(fileName)
    arguments
        fileName % This should be a string, the name of the image you want to read
    end
    A = double(imread(fileName)); % Converts image to matrix of doubles
end

Answer 1

[yanqi liu]

A = readMyPicture("cameraman.tif");
figure; imshow(A, []);

function A = readMyPicture (fileName)
A = [];
if nargin < 1
    return
end
try
A= double(imread(fileName)); % Converts image to matrix of doubles
catch
end
end

Answer 2

[Image Analyst]

Get rid of the "arguments" and "end" line. They are not needed. Or use @yanqi liu's solution for more robustness.