清空筛选条件
清空筛选条件

How does the function "imresize" work in details ?

29 次查看（过去 30 天）
Chakib
Chakib 2013-7-23
评论： Rafi Ahmed 2021-7-16
During my internship I discovered the function "imresize" which I used it to enhance the resolution of images (for example : I transformed a 32x32 image into a 128x128 image) and it gave me really good results.
So I read the code of the function and it didn't help me to understand it.
So I am asking you to explain to me how it works or to give me links to articles and publications on resolution enhancement theories. The second choice would be better for me.
Thanks to all and sorry for my english.
BELAFDIL Chakib

请先登录，再回答此问题。

采纳的回答

Elad
Elad 2013-7-23
I'm not sure, (did'nt look at the function's code). but, probably using some kind of bi-linear interrpolation: http://en.wikipedia.org/wiki/Bilinear_interpolation

更多回答（1 个）

Alex Taylor
Alex Taylor 2013-7-23
I would take at the series on spatial transformations from Steve on Image Processing, starting with Terminology and Notation:
http://blogs.mathworks.com/steve/category/spatial-transforms/
Imresize is simply applying a scale transformation to the original image. You could think of this operation as the application of the following affine transformation matrix to the original image:
T = [4 0 0; 0 4 0; 0 0 1];
Imresize uses inverse mapping to figure out where each point in the output grid maps in the input grid. We then interpolate within the input grid to determine the output grid values. By default, imresize uses bicubic interpolation by default.
Applying a scale geometric transformation to an image is not a "resolution enhancement" technique. You do not have any more information in the output image than you started with in the input image, you have simply interpolated to create a larger grid than you started with.
This is not applicable to your particular problem, because you are increasing the size of your original image, but if you resize with a scale factor of less than 1, imresize applies an anti-aliasing filter prior to resizing.
  1 个评论
Rafi Ahmed
Rafi Ahmed 2021-7-16
Hello Alex,
I have a question regarding the grid values. If I slice an image for the row elements only (e.g. 360 by 360 grid image is sliced to 180 by 360), how does that affect the grid size and values? Does it reduce the grid values too?

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Image Filtering and Enhancement 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