read 20 images in ordered manner

1 次查看（过去 30 天）
talayeh ghodsi
talayeh ghodsi 2019-10-13
编辑： Image Analyst 2019-10-13
Hi everybody. I have 20 images named 1.png,2.png,...,20.png
I want to read them in ordered manner and save them in a matrix called pic_3D. I wrote this code:
surf_read_dir='E:\phd\zahra taati\extract only heart\h70%\';
files=dir('E:\phd\zahra taati\extract only heart\h70%\*.jpg');
for im=1:size(files)
fdir = strcat(surf_read_dir , files(im).name);
slice_im = load(fdir);
pic = imread(fdir);
for i=1:500
frt_data(im,:,i)=pic(i,:,1);
end
pic_3D(:,:,im) = pic(:,:,1);
end
end
but it doesn't read them from 1 to 20 in order and it reads them randomly. For example it saves 20.png before 5.png.
How should I correct my code?

请先登录，再回答此问题。

回答（2 个）

Walter Roberson
Walter Roberson 2019-10-13
See the File Exchange contribution https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort
Or, in your case because you know the file names are sequential, you could skip the dir() step and use
for im = 1 : 20
fdir = fullfile(surf_read_dir, sprintf('%d.png'));
pic = imread(fdir);
frt_data(im, :, :) = pic(1:500,:,1);
pic_3D(:,:,im) = pic(:,,:,1);
end
I would suggest, though, that instead of constructing frd_data at that point, that instead you construct just pic_3D in the loop, and then after the loop,
frt_data = permute( pic_3D(1:500,:,:), [2 3 1]);
Image Analyst
Image Analyst 2019-10-13
编辑：Image Analyst 2019-10-13
Part of the problem was in using a file pattern of *.jpg when you actually have *.png files. But also other errors. Try this (untested):
surf_read_dir='E:\phd\zahra taati\extract only heart\h70%\';
filePattern = fullfile(surf_read_dir, '*.png');
files = dir(filePattern)
for k = 1 : length(files) % May be 20 or whatever - this makes it not matter - it will do them all.
baseFileName = sprintf('%k.PNG', k);
fullFileName = fullfile(files(k).folder , baseFileName);
if ~isfile(fullFileName)
fprintf('%s not found. Skipping slice %d.\n', fullFileName, k);
continue;
end
thisSlice = imread(fullFileName);
[rows, columns, numberOfColorChannels] = size(thisSlice);
if numberOfColorChannels > 1
thisSlice = thisSlice(:, :, 1); % Take red channel.
end
if k == 1
frt_data = zeros(rows, columns, length(files), 'uint8');
end
frt_data(:,:, k) = thisSlice;
fprintf('Inserting slice %d (%s) into 3-D array.\n', k, baseFileName);
end
pic_3D = frt_data; % Another variable with the same name for some reason.

类别

在 Help Center 和 File Exchange 中查找有关 Image Segmentation and Analysis 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