How do i randomly show the pictures i have in my array?

this is my code:

folder = 'F:\school\matlab\project\pictures\pictures alone'

filePattern = fullfile(folder, 'apple.jpg','condor.jpg','elephant.jpg',...
    'Koala.jpg','orange.jpg','whale.jpg','Penguins.jpg');

i would like to use imshow() to show the pictures but i want it to show random pictures from the filePattern i declared above... can anyone please help me with this?

i am using matlab R2013a

Answer 1

[Guillaume]

Your usage of fullfile is incorrect. The arguments you pass except for the last should be folder.

There are many ways to do what you want. The gist of it is to store your options in a cell array and choose an element at random with any of the random functions, randi for example. Or just reorder the array with randperm.

folder = 'F:\school\matlab\project\pictures\pictures alone';
files = {'apple.jpg','condor.jpg','elephant.jpg',...
  'Koala.jpg','orange.jpg','whale.jpg','Penguins.jpg'};

%pick one at random and show:
imshow(fullfile(folder, files{randi(numel(files))}));
pause(5)
%pick another at random, it may be the same
imshow(fullfile(folder, files{randi(numel(files))}));

%reorder the array randomly:
randomisedfiles = files(randperm(numel(files)));
%etc.

[Glenn Macion]

thank you so much.... i needed this... i'm quiet new to this programming thing.. so i'm trying to learn more about programming and matlab...

is there a way to link different words to each ".jpg' picture in that array...? i have a feeling that it might be possible but i just don't know how...

like say, i would like the word apple to be linked with 'apple.jpg' so that when i see the apple picture and i type apple it will give me a positive response... i have been searching the web about this.. and i cant find a way to do it... well i might had already found the answer but i probably didn't understand it... i'm sorry if i'm being too demanding.. just wanted to explore this matlab programming.. coz it's my first time to do programming.... and i'm very excited to try lots of things with this....

[Guillaume]

I'm not very clear on what you're asking. It sounds like you're after a method of tagging pictures and retrieving / searching these tags.

This is normally done with a database or some data structures that are not available in matlab (e.g. multi-index container). In matlab, what I would do is use a map.

If you wanted to make it easy to find images associated with a certain tag, the tags would be the keys, the images associated with the tag, the values, would be a cell array:

keys = {'fruits', 'animals', 'apples', 'birds'};
values = {{'apple.jpg', 'orange.jpg'}, {'condor.jpg', 'elephant.jpg', 'koala.jpg', 'whale.jpg', 'penguins.jpg'}, {'apple.jpg'}, {'condor.jpg', 'penguins.jpg}};
tagimages = containers.Map(keys, values);

%find images of birds:
birdimages = tagimages('birds')

%add a tag:
tagimages('Four legged') = {'elephant.jpg', 'koala.jpg'}

The issue with the above is that you duplicate the image strings a lot in the map (that can be worked around by storing indices to the cell array of filenames instead) and finding the tags associated with one image is not easy. Matlab unfortunately does not have a great deal of containers. To get something better, you'd have to use the database toolbox.

If what you want to do predominantly is find tags associated with an image, then you make the images the keys, and the tags the values:

keys = {'apple.jpg', 'orange.jpg', 'condor.jpg', 'elephant.jpg', 'koala.jpg', 'whale.jpg', 'penguins.jpg'};
values = {'fruit', 'apple'}, {'fruit'}, {'animal', 'bird'}, {'animal'}, {'animal'}, {'animal'}, {'animal', 'bird'}};
imagetags  = containers.Map(keys, values);

appletags = imagetags('apple.jpg')

[Glenn Macion]

thanks for your answer again... you have been very helpful...

i have another question ... i apologize if i sound very stupid about this... this is my first time trying programming... and i don't really learn fast by reading... but through the examples and answers you guys have given, i have been learning a lot so far... thank you... my other question is,... is there a way to not randomly show the pictures?

folder = 'F:\school\matlab\project\pictures\pictures alone'; files = {'apple.jpg','condor.jpg','elephant.jpg',... 'Koala.jpg','orange.jpg','whale.jpg','Penguins.jpg'};

%pick one at random and show: imshow(fullfile(folder, files{randi(numel(files))})); pause(5) %pick another at random, it may be the same imshow(fullfile(folder, files{randi(numel(files))}));

%reorder the array randomly: randomisedfiles = files(randperm(numel(files))); %etc.

like, what if i decide to show it according to how it has been sorted, respectively... i mean... from apple.jpg to Penguins.jpg... how do i use imshow(); to display it from the first row, first column to the last row and column of the array instead of doing it randomly..?