Question

我在编程上还很陌生，正在尝试使用Psychtoolbox编写我的第一个实验。在此实验中，将显示随机数量的面孔（1-6个面孔），并且每个面孔都彼此不同。这些面孔将在2秒钟后消失，然后出现一个探针面孔2秒钟。参与者必须确定探测面是否在先前的一组面中。使用我当前的代码，呈现的面孔数量正在随机化。但是我的问题是，学习阶段中显示的面孔始终是相同的（例如，如果显示了5张面孔，则在所有5个位置上都是相同的面孔）。相同的面孔将出现6次（完成循环时p = 1：6），直到显示出新面孔为止，但问题是相同的面孔始终出现。有没有一种方法可以使每次显示一张新面孔？

f = 1
ntrials = 20;
for i = 1:ntrials

  positions = Shuffle(1:6); %positions = the number of faces that will be shown (randomized)


           folder = '/Users/ricelab06/cropped_faces';
           fileFull = fullfile(folder, {'*.jpg'});
           files = dir(fileFull{1});
           images = cell(1, 1);  
           currentfilename = files(imgs(f)).name;
           fullFileName = fullfile(folder, currentfilename);
           currentimage = imread(fullFileName);
           images{imgs(f)} = currentimage;
           randFaceTexture = Screen('MakeTexture', window, currentimage);
           [imageHeight, imageWidth, colorChannels] = size(currentimage);

           f = f + 1;


for k = 1:6
     if positions(k) == 1  %1 face is shown 
         for p = 1:positions(k)             
                %Draw the images to the back buffer
                Screen('DrawTexture', window, randFaceTexture, [], []);

         end

     elseif positions(k) == 2 %2 faces are shown 
         for p = 1:positions(k)
                posLine = {line1, line2}; 
                %Draw the images to the back buffer 
                Screen('DrawTexture', window, randFaceTexture, [], [posLine{p}]);

         end

     elseif positions(k) == 3 %3 faces are shown 
         for p = 1:positions(k)
                posTriangle = {triangle1, triangle2, triangle3};                 
                %Draw the images to the back buffer
                Screen('DrawTexture', window, randFaceTexture, [], [posTriangle{p}]);

         end  

     elseif positions(k) == 4  %4 faces are shown 
         for p = 1:positions(k)
                posSquare = {square1, square2, square3, square4};                 
                %Draw the images to the back buffer
                Screen('DrawTexture', window, randFaceTexture, [], [posSquare{p}]);

         end

     elseif positions(k) == 5  %5 faces are shown 
         for p = 1:positions(k)
                posPentagon = {pentagon1, pentagon2, pentagon3, pentagon4, pentagon5};                      
                %Draw the images to the back buffer
                Screen('DrawTexture', window, randFaceTexture, [], [posPentagon{p}]);

         end      

     elseif positions(k) == 6  %6 faces are shown
         for p = 1:positions(k)
                posHexagon = {hexagon1, hexagon2, hexagon3, hexagon4, hexagon5, hexagon6};                       
                %Draw the images to the back buffer
                Screen('DrawTexture', window, randFaceTexture, [], [posHexagon{p}]);

         end 
     end     
end

Screen('Flip', window);
WaitSecs(2);

Answer 1

由于在k = 1：6循环之外定义了面部索引（定义为变量“ f”），因此显示了同一张面部。因此，相同的'f'值将用于为所有k值加载图像纹理。

尚不清楚您是否有6张面部图像或更大的图像集。但是在k = 1：6循环中的每次运行中，您都可以通过以下方式选择k个唯一的人脸索引：

n = 10; % unclear your actual value of total face images
% choose 'k' values out of 'n' (without replacement)
faces_to_display = ChooseKFromN(n, k);

然后，您可以通过将这些面部图像作为纹理加载（或从数组中选择纹理，如果预先加载），在“ faces_to_display”中显示这些面部的索引。

实际上，在随机选择数据时，您还需要添加：

% reseed random number generatetor
ClockRandSeed()

在脚本顶部，确保随机数生成器在两次运行之间选择不同的值。

使用Psychtoolbox呈现新的随机图像的麻烦

1 个答案: