perfmance: "imageDatastore" low performance when specifying multiple file names directly

Question

cui,xingxing 2022-12-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1872012-perfmance-imagedatastore-low-performance-when-specifying-multiple-file-names-directly

回答： Rahul 2025-5-5

采纳的回答： Rahul

在 MATLAB Online 中打开

Very low performance when specifying multiple image full path names for a given imageDatastore，see benchmark below.

env: matlab 2022b， win10

imgsDir = "someImgDir";
imgNames = imgsDir+"/"+string(0:2687)+".jpg";% The more images you have, the lower the performance
t1 = tic;
for i = 1:10
    imds = imageDatastore(imgNames); % low
end
t = toc(t1)
t2 = tic;
for i = 1:10
    imds = imageDatastore(imgsDir); % high
end
t = toc(t2)

t =

14.0975

t =

0.5759

Initially I wanted to sort the files in the ImageDatastore by Arabic arrays, but found the above to be a real performance problem, any better suggestions?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Rahul 2025-5-5

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1872012-perfmance-imagedatastore-low-performance-when-specifying-multiple-file-names-directly#answer_1564683

在 MATLAB Online 中打开

Hi @cui,xingxing,

I understand that reading images while specifying the image names is causing performance issues as compared to reading directly from a folder. However, reading from a folder would limit the ability to sort it before reading.

Here are a few suggestions which could improve the performance of your use-case:

Sort the images after reading them. This can be done by extracting the filenames and then sorting them. Here is an example:

imds = imageDatastore(imgsDir);
% Extract file names and sort numerically
[~, name, ext] = cellfun(@fileparts, imds.Files, 'UniformOutput', false);
nums = str2double(name);
[~, idx] = sort(nums);
% Reorder imds.Files
imds.Files = imds.Files(idx);