Matlab image spatial resolution, change pixel

2022 3 19
3 个回答
回答已采纳
更新时间：2022 3 20
11 次查看（30 天）

 采纳的回答

Image Analyst
Image Analyst 2022-3-19
Ran in:

0 个投票

Ran in:
Try this. It will make sure the output image is exactly the same size as the input image.
inputImage = imread('peppers.png');
[inputRows, inputColumns, numColors] = size(inputImage)
inputRows = 384
inputColumns = 512
numColors = 3
for ii = 1:6
subplot(2,3,ii);
outputImage = imresize(inputImage,2^-(ii-1));
[rows, columns, numColors] = size(outputImage);
fprintf('After resizing once it is %d rows by %d columns\n', rows, columns);
% Resize output image again to match the input.
outputImage = imresize(outputImage, [inputRows, inputColumns], 'nearest');
% Update size.
[rows, columns, numColors] = size(outputImage);
fprintf(' After resizing twice it is again %d rows by %d columns\n', rows, columns);
imshow(outputImage);
% Show title with new size.
caption = sprintf('%d rows by %d columns', rows, columns);
axis('on', 'image')
title(caption)
end
After resizing once it is 384 rows by 512 columns
After resizing twice it is again 384 rows by 512 columns
After resizing once it is 192 rows by 256 columns
After resizing twice it is again 384 rows by 512 columns
After resizing once it is 96 rows by 128 columns
After resizing twice it is again 384 rows by 512 columns
After resizing once it is 48 rows by 64 columns
After resizing twice it is again 384 rows by 512 columns
After resizing once it is 24 rows by 32 columns
After resizing twice it is again 384 rows by 512 columns
After resizing once it is 12 rows by 16 columns
After resizing twice it is again 384 rows by 512 columns

更多回答（2 个）

Voss
Voss 2022-3-19
Ran in:

1 个投票

Ran in:
You can try imresize()
im = imread('image_1.png');
for ii = 1:6
subplot(2,3,ii);
imshow(imresize(im,2^-(ii-1)));
end

9 个评论
显示 7更早的评论 隐藏 7更早的评论

akevg akevg
akevg akevg 2022-3-19
thank you so much . it worked for me
Voss
Voss 2022-3-19
Since it worked, do you mind accepting the answer? I appreciate it!
Image Analyst
Image Analyst 2022-3-19
编辑：Image Analyst 2022-3-19
@akevg akevg Note that the output image size is different than the original. With my code below, the image size is the same, it's just blockier looking. Do you want the output image size to be the same or smaller?
Image Analyst
Image Analyst 2022-3-19
编辑：Image Analyst 2022-3-19
Ran in:
Ran in:
Then you accepted the wrong answer. Watch this:
im = imread('peppers.png');
for ii = 1:6
subplot(2,3,ii);
outputImage = imresize(im,2^-(ii-1));
imshow(outputImage);
axis('on', 'image')
[rows, columns, numColors] = size(outputImage)
caption = sprintf('%d rows by %d columns', rows, columns);
title(caption)
end
rows = 384
columns = 512
numColors = 3
rows = 192
columns = 256
numColors = 3
rows = 96
columns = 128
numColors = 3
rows = 48
columns = 64
numColors = 3
rows = 24
columns = 32
numColors = 3
rows = 12
columns = 16
numColors = 3
Voss
Voss 2022-3-19
I appreciate that you accepted my answer. However, if you want the same image size, go with @Image Analyst's answer and accept it instead.
DGM
DGM 2022-3-20
Ran in:
Ran in:
Or you could just do
inpict = imread('peppers.png');
k = 16;
outpict = imresize(imresize(inpict,1/k,'bilinear'),k,'nearest');
imshow(outpict)
[size(inpict); size(outpict)]
ans = 2×3
384 512 3 384 512 3
Which is far simpler and much faster than using blockproc() for any moderately large image.
Of course, it depends how much control one wants over exactly which pixels are contributing to each block and how exactly they're being weighted. I'm assuming that the goal here has no technical requirements, as none were given.

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Convert Image Type 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