How to solve error "Error using bwmorph"

I want to doing a feature extraction steps for multiple images, i have this function:

% this function is supposed to extract features from the input image

function [features]=feature_extraction(I)

if length(size(I))>2 % checking if rgb image;
  I=im2bw(I,graythresh(I));
end    

I=bwmorph(I,'skel',inf);

I=discourser(I);

row=size(I,1);
column=size(I,2); ... and so on.

And I call it in another script.

files = dir('*.png');

for i = 1:numel(files)

I = files(i).name;

[getfeature] = feature_extraction(I);
end

[Walter Roberson]

You omitted the error message.

[ana ain]

I sorry, the following is the error message:

Error using bwmorph Expected input number 1, BW, to be one of these types:

double, single, uint8, uint16, uint32, uint64, int8, int16, int32, int64, logical

Instead its type was char.

Error in bwmorph (line 91) validateattributes(bwin,{'numeric' 'logical'},{'real' 'nonsparse' '2d'}, ...

Error in feature_extraction (line 13) I=bwmorph(I,'skel',inf);

[Walter Roberson]

Yes, to be expected when you pass in the name of the file instead of the content of the file.

[ana ain]

could you please explain using some example? Thank you :)

[Walter Roberson]

I understand that. What I'm saying is that if you put the responses into into a file and then run

myexe.exe < c:\temp\inputs.txt

in the command shell and then, assuming that works,

system('myexe.exe < c:\temp\inputs.txt')

does it work?

Answer 1

[Walter Roberson]

You are passing the file name into the function. The name of the file does not have more than 2 dimensions so you do not use im2bw(). You are passing the name of the file to bwmorph. bwmorph is not defined for character strings.

Have you considered the possibility of reading the file content at some point?