saving an image to disk

9 次查看（过去 30 天）
Karan Ratnaparkhi
Karan Ratnaparkhi 2011-4-27
编辑： DGM 2021-6-3
Hi guys, after some processing i am getting an image and now I want to save it to my disk in .png format. Plz tell me which function should I use?

请先登录，再回答此问题。

回答（2 个）

Chirag Gupta
Chirag Gupta 2011-4-27
Rahul punk
Rahul punk 2021-6-2
编辑：Rahul punk 2021-6-3
%read image
tt= imshow(image) ;
%save your image other location with any name save desktop or any folder also
saveas(tt,'C:\Users\admin\Desktop\testimagesave.png') ;
  2 个评论
Rik
Rik 2021-6-2
This uses a much more complex method, making it much slower. It also risks changing the apearance of the image, as well as adding a border around the axes containing the image.
Also, the question asked for a png, so I don't see why you chose jpg in your example. I would also discourage using imshow to read an image from disk. It is much clearer what is happening if you use imread.
DGM
DGM 2021-6-3
编辑：DGM 2021-6-3
To emphasise what Rik mentioned, by default, imshow() uses nearest-neighbor interpolation to display the image. Even disregarding the added padding, the actual size of the image will depend on the figure geometry. If it is resized, it will be subject to all the degradation associated with nearest-neighbor interpolation. For example:
% generate a 500x500 1px checkerboard pattern
x = mod(1:500,2);
y = mod(1:500,2);
inpict = xor(x,y');
% look! it's perfect!
imwrite(inpict,'justwritethefile.png');
Okay, maybe it doesn't look perfect, but that's just the website messing with how it's displayed. Just right click > view image to see it straight.
If you use imshow(), this is what you get. I added 1px black border so it's easier to see how big it is against the webpage bg.
tt = imshow(inpict);
saveas(tt,'whywouldyoudothis.png')
Go ahead and right click > view image on this one. Look at all that padding. Look at all the interference. This is not a negligible or reversible amount of damage. Could some of this be avoided by getting the figure geometry just right? Sure, but the figure geometry can't always be right, and there's no reason to add the extra complexity for a small improvement upon a self-made problem.
Add to this the fact that imshow() can't handle alpha content, so any alpha content will be lost. Similarly, any indexed image saved this way will no longer be an indexed image -- something which imwrite supports for PNGs.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Convert Image Type 的更多信息

标签

产品

Community Treasure Hunt

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

Start Hunting!

Translated by