MATLAB: How to choose image

Image Processing Toolboximreadrandom imagerandperm

Hi all,

I'm initially randomly choosing two images from a folder (both with different specifications) and then I want to randomly display one on the left and one on the right. However, I don't know how to do the randomization before selecting them for either left or right.

Best Answer

Do not store them in two separate variables, but use a cell or struct array! It is the contents of variable that should vary, not the name ...

img{1} = imread( i1 );
img{2} = imread( i2 );
%drawing it on the back buffer
X = randperm(2) % [1 2] in random order 
myTexture = Screen( 'MakeTexture', window, img{X(1)} );  
Screen( 'DrawTexture', window, myTexture, [], rectL );
myTexture2 = Screen( 'MakeTexture', window, img{X(2)} );
Screen( 'DrawTexture', window, myTexture2, [], rectR );

Related Solutions

MATLAB: Random display of 1 out of several images

You could read all the images into a cell array (each image in an element), then:

for k=1:8
    imageCell{k}=imread([num2str(k),'.bmp']);
end
imshow(imageCell{randi(8)});

MATLAB: How to present two streams of images on one screen simultaneously

One way to do this is to use a timer callback functions: https://www.mathworks.com/help/matlab/ref/timer-class.html. For example, try the following code

im1 = imread('peacock.jpg');
im2 = imread('pears.png');
im3 = imread('cameraman.tif');
im4 = imread('carsinfront.png');
fig1 = figure();
ax1 = axes();
fig2 = figure();
ax2 = axes();
% timers for figure 1
% period of both timers is 1 + 0.5 = 1.5 seconds
% an initial delay of 0.5 is given for t1 to give some time for setup
% an initial delay of 0.5 + 1 = 1.5 is given to t2, since it need to
% lag t1 by 1 second.
t1 = timer('ExecutionMode', 'fixedRate', 'Period', 1.5, ...
    'TimerFcn', {@timerFcn, ax1, im1}, 'StartDelay', 0.5);
t2 = timer('ExecutionMode', 'fixedRate', 'Period', 1.5, ...
    'TimerFcn', {@timerFcn, ax1, im2}, 'StartDelay', 1.5);
t1.UserData.count = 1;
t1.UserData.max_count = 10;
t2.UserData.count = 1;
t2.UserData.max_count = 10;
% timers for figure 2
t3 = timer('ExecutionMode', 'fixedRate', 'Period', 1, ...
    'TimerFcn', {@timerFcn, ax2, im3}, 'StartDelay', 0.5);
t4 = timer('ExecutionMode', 'fixedRate', 'Period', 1, ...
    'TimerFcn', {@timerFcn, ax2, im4}, 'StartDelay', 1.2);
t3.UserData.count = 1;
t3.UserData.max_count = 10;
t4.UserData.count = 1;
t4.UserData.max_count = 10;
start(t1);
start(t2);
start(t3);
start(t4);
function timerFcn(obj, event, ax, im)
    imshow(im, 'Parent', ax);
    if obj.UserData.count == obj.UserData.max_count
        stop(obj);
        delete(obj);
    else
        obj.UserData.count = obj.UserData.count + 1;
    end
end

Best Answer

Related Solutions

MATLAB: Random display of 1 out of several images

MATLAB: How to present two streams of images on one screen simultaneously

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