MATLAB: How to load random image from folder

dirimageImage Processing ToolboximreadMATLABrandi

Hello. I have 4 images in 1 folder and I have to load them randomly. I tried to do this.
>> a=dir(['C:\Users\Desktop\Crossroad\vehicles' '/*.png'])
and then randomly load one of 4 images 
im=imread(a(randi(4)).name)
but matlab gives me an error:
Error using imread (line 349)
File "white_car.PNG" does not exist.
It. wrotes that files doesnt exist, but it actually does..Does anyone know how to write it properly? Many thanks.

Best Answer

You need to use fullfile because a(index).name does not include the folder.
folder = 'C:\Users\Desktop\Crossroad\vehicles'
fileList = dir(fullfile(folder, '/*.png'))
randomIndex = randi(length(fileList), 1, 1) % Get random number.
fullFileName = fullfile(folder, fileList(randomIndex).name)
img = imread(fullFileName);
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