显示所需帧数的静态图像序列时出现的问题MATLAB

Question

我必须向我的参与者展示一系列的视觉刺激，每个刺激持续一定数量的帧。每个刺激都编码为一个数字(在stimuli_matrix中报告)，其应持续的帧数在stimframesVector中报告。stimuli_matrix行代表试验。

我的问题是，对于指定的帧数，刺激没有显示出来。作为另一种选择，我试图创建一个矩阵，其中包含:试验应该持续的帧数和要呈现的刺激序列，我只获得了一个闪烁的、不准确的和错误的(时间方向)刺激呈现。你能帮助我改进代码，使其显示指定数量的帧的刺激而不闪烁吗？

以下是代码

vbl = Screen('Flip', window);

ifi = Screen('GetFlipInterval', window);

Screen('Flip',window);


for righe=1:size(stimuli_matrix,1)

    for prov=1:size(stimuli_matrix,2)
        waitframes=1;
        stimduration = .5;
        begduration = 1;
        rndnumb=rand;
        jitter= (rndnumb-0.5)*0.1;
        Jittered_stim = stimduration + jitter;
        Jittered_beg = begduration + jitter;
        
        % How long should the image stay up in frames
        
        Stim_Frames = round(Jittered_stim / ifi);
        
        % Duration in frames of trial start
        
        Beg_Frames = round(Jittered_beg / ifi);
        
        stimframesVector=ones(1,Stim_Frames);
        indice=stimuli_matrix(righe,prov)
        
        %stimframesVector1=stimframesVector(1)*1
        [keyIsDown,secs, keyCode] = KbCheck;
        if keyCode(escapeKey)
            sca;
        end
         tic;
        for frames=1:length(stimframesVector)
            if indice==0
                Screen('DrawLines', window, allCoords,lineWidthPix, white, [xCenter yCenter], 2);
                Screen('Flip', window, [], 1);
            elseif indice == 1
                Screen('DrawTextures', window, D1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 2
                Screen('DrawTextures', window, C1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 3
                Screen('DrawTextures', window, B1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 4
                Screen('DrawTextures', window, A1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 5
                Screen('DrawTextures', window, H1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 6
                Screen('DrawTextures', window, G1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif indice == 7
                Screen('DrawTextures', window, F1, [], allRects,0);
                Screen('Flip', window, [], 1);
            elseif  indice == 8
                Screen('DrawTextures', window, E1, [], allRects,0);
                Screen('Flip', window, [], 1);
            end
        end
     Screen('Flip', window, vbl+(waitframes-0.5)*ifi);
     stimvec2=stimframesVector %checking time
      toc; 
    end
end

Answer 1

我认为问题在于，您没有指定何时使用Screen Flip命令翻转刺激序列中的每个刺激。下面是一个简化的示例，它根据帧生成具有随机颜色和随机时间间隔的椭圆形序列。关键是每个屏幕Flip命令都包括第三个参数，该参数指示应呈现刺激的心理工具箱时间。

try
    screenNum= max(Screen('Screens'));
    [wPtr, wRect]=PsychImaging('OpenWindow', screenNum, 0);
    ifi = Screen('GetFlipInterval', wPtr);
    
    number_stim = 10;
    stimuli_colors = round(rand(number_stim, 3) * 255);
    frame_deltas = 15 + round(rand(number_stim, 1) * 15);
   
    % initial flip
    [~, lastOnset] = Screen('Flip', wPtr);
    for f = 1:number_stim
        Screen('FillOval', wPtr, stimuli_colors(f, :), CenterRect([0 0, 400, 400], wRect));
        [~, lastOnset] = Screen('Flip', wPtr, lastOnset + ((frame_deltas(f) - 0.5) * ifi));
    end
   
    sca;
    
catch e
    sca;
    rethrow(e)
end