Presenting faces at random without repetition

2022 12 18
1 个回答
回答已采纳
更新时间：2022 12 19
7 次查看（30 天）

0 个投票

I need help in presenting a set of images (10 in total, at random without any repetitions. In the files, however, I have a total of 20 images and only certain specific pictures have been decided to be presented. How do I specify such criteria? Also, I tried to insert a specification where each of the pictures will be presented for 2 seconds but could not seem to figure out where shall the code be put at.
The following are the codes that I have written but it does not seem to comply. If there are any correction please do help me.
%loop start for recognition phase
%where my codes actualy START
A = imread('matlabfaces');
B = ['x','y','z'];
C = B(randi(numel(B)));
files = dir('matlabfaces'); %specify again the file location
numberoffiles = length(files); %total amount of files?
randomIndexs = randperm(numberoffiles); %randomise the files
%start loop
for j = 1:numberoffiles
thisFilename = files(randomIndexs(j)).name;
rgbimage = imread('matlabfaces');
image (rgbimage);
axis('image', 'off');
pause(3);
end
sca;

1 个评论
显示 -1更早的评论 隐藏 -1更早的评论

John D'Errico
John D'Errico 2022-12-19
编辑：John D'Errico 2022-12-19
Please don't keep on posting the same question. If you don't understand the answer, then say so, and ask for further explanation.

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

John D'Errico
John D'Errico 2022-12-18
编辑：John D'Errico 2022-12-19
Ran in:

0 个投票

Ran in:
Pick the 10 images to be shown immediately, as 10 numbers from the set 1:23, WITHOUT replaceemt. randperm will do that for you. Then just display the chosen images in that sequence.
help randperm
RANDPERM Random permutation. P = RANDPERM(N) returns a vector containing a random permutation of the integers 1:N. For example, RANDPERM(6) might be [2 4 5 6 1 3]. P = RANDPERM(N,K) returns a row vector containing K unique integers selected randomly from 1:N. For example, RANDPERM(6,3) might be [4 2 5]. RANDPERM(N,K) returns a vector of K unique values. This is sometimes referred to as a K-permutation of 1:N or as sampling without replacement. To allow repeated values in the selection, sometimes referred to as sampling with replacement, use RANDI(N,1,K). RANDPERM calls RAND and therefore changes the state of the random number generator that underlies RAND, RANDI, and RANDN. Control that shared generator using RNG. See also NCHOOSEK, PERMS, RAND, RANDI, RNG. Documentation for randperm doc randperm Other uses of randperm gpuArray/randperm RandStream/randperm
So all you need is
randomIndexs = randperm(numberoffiles,10); %randomise the files
ans = 1×10
1 7 3 20 8 22 9 4 14 18
And now your for loop will start out as:
for j = 1:10
As far as the 2 second pause goes, you already have it doing a 3 second pause. That is what pause(3) should do. Perhaps you are not counting the seconds carefully when you look at it? Or perhaps, even though you say you want a 2 second pause, you really want a longer pause and do not realize it?

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Code Generation for ARM Cortex-M and ARM Cortex-A Processors 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by