How read multiple image to Matlab memory

I would like to aks You how can I read a multiple image to Matlab ? I have n foto in Folder on my laptop and I need to put all of them into Matlab memory and then I need to convert image to binary image and after that I need convert all my image to double precision. I try make it with for loop but I have no idea how should to do. All od this steps are needed because I would like to make a Neural Network to Recognize a Road Sing. Now I have something like that:

% B=imread('A6E.png'); %Image 1

% B=im2bw(B);

% B=double(B);

%

% C=imread('A6D.png'); %Image 2

% C=im2bw(C);

% C=double(C);

True is, in this way I need all day to put all of my patterns. Someone give me some advice ?

Thank You.

[Stephen23]

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

[Stephen23]

Pawel Osadnik's "Answer" moved here:

function results = myvarfcn(var)
image = imread(var);
imBW = im2bw(image);
imDouble = double(imBW);
reimage = reshape(imDouble,40000,1);
results.image = image; 
results.imBW = imBW;
results.imDouble = imDouble;
results.reimage = reimage;
end

I have something like this and it is working, but... Answer is 1-by-1 structure with all (4) results. Ok, but how can I upload (all at once) files into this function ? And after that I need one big structure or many structure with results from my files.

For my NN need one Matrix with all patterns.

Thank.

Answer 1

[Florian Morsch]

You could use the the Image Batch Processor if you have it at hand: https://de.mathworks.com/help/images/batch-processing-using-the-image-batch-processor-app.html

Here you can load all images from a file and do something with them ( Your function would look something like this:

function results = myimfcn(im)
%Image Processing Function
%
% IM      - Input image.
% RESULTS - A scalar structure with the processing results.
%

%--------------------------------------------------------------------------
% Auto-generated by imageBatchProcessor App. 
%
% When used by the App, this function will be called for every input image
% file automatically. IM contains the input image as a matrix. RESULTS is a
% scalar structure containing the results of this processing function.
%
%--------------------------------------------------------------------------

% Replace the sample below with your code----------------------------------

      imBW = im2bw(im);

      imDouble = double(imBW);

results.imBW = imBW;
results.imDouble = imDouble;

%--------------------------------------------------------------------------

The batch processor app loads all images you tell it, uses the function you insert on the images and then you can save the results as you please.

[Pawel Osadnik]

Ok but how can I put into this function my files ? I try:

function results = myimfcn(im)

im = imread('K9.png'); %name of my file but I have a lot of this file.

% IM - Input image. % RESULTS - A scalar structure with the processing results. % %-------------------------------------------------------------------------- % Auto-generated by imageBatchProcessor App. % % When used by the App, this function will be called for every input image % file automatically. IM contains the input image as a matrix. RESULTS is a % scalar structure containing the results of this processing function. % %-------------------------------------------------------------------------- % Replace the sample below with your code----------------------------------

      imBW = im2bw(im);

      imDouble = double(imBW);

results.imBW = imBW;

results.imDouble = imDouble; %-------------------------------------------------------------------------- end

[Florian Morsch]

The function i gave you works with the Image Batch Processor App as i told you in the first line. Open the app, load your pictures, fill in the function i gave and just press "process all images", done.

[Pawel Osadnik]

Thank You for help, it working.

I recive struct in Mablab with my variable but how I can put this into P matrix ?

[Stephen23]

@Pawel Osadnik: Your function definition is part of the problem:

function results = myimfcn(im)
im = imread('K9.png');

The input im (whatever it might be) is completely ignored because you totally redefine im on the first line of code. If you actually want to use the input values (e.g. when calling then function in a loop, which is the solution to your question), then redefining im inside the function does not help you.

[Pawel Osadnik]

I now about it, my mistake. I change this for code: And use Image Batch Processor App.

function results = myimfcn(im) %Image Processing Function % % IM - Input image. % RESULTS - A scalar structure with the processing results. %

%-------------------------------------------------------------------------- % Auto-generated by imageBatchProcessor App. % % When used by the App, this function will be called for every input image % file automatically. IM contains the input image as a matrix. RESULTS is a % scalar structure containing the results of this processing function. % %-------------------------------------------------------------------------- % Replace the sample below with your code----------------------------------

imBW = im2bw(im);

imDouble = double(imBW);

imReshape = reshape(imDouble,40000,1);

results.imBW = imBW;

results.imDouble = imDouble;

results.imReshape = imReshape;

And now I have my files in matlab but as Struct. And this problem because NN need matrix. My one cell in struct is a 40000x1 and this I need to have in my Workspace.

imReshape

____________

40000x1 double % This I need to have in Workspace as a single Matrix

40000x1 double

40000x1 double

40000x1 double

etc

Any idea how to "convert" struct to matrix ?

Answer 2

[Pawel Osadnik]

I make it. Thank for Your help.