In matlab I had seen many commands to resize the images but i didn't get the clear idea about the algorithm behind it. Can anyone explains me about the bi-linear/bi-cubic/nearest neighbor algorithm to down sample the image?
I am having the image of size 900*1200*3 Can anyone explains how can I make it 64*64 image size?
Thank You
Dear Madhuri,
Please use the following command in Matlab
newimage= imresize(oldimage, [64 64],'bilinear')
Best regards
Dear Madhuri,
you can also see the following links for more details about interpolation
https://en.wikipedia.org/wiki/Bilinear_interpolation
you can also read
the 2nd edition of Digital Image Processing Using MATLAB. it has a brand new chapter called Geometric Transformations and Image Registration.
Here are the chapter contents:
Chapter 6: Geometric Transformations and Image Registration
6.1 Transforming Points
6.2 Affine Transformations
6.3 Projective Transformations
6.4 Applying Geometric Transformations to Images
6.5 Image Coordinate Systems in MATLAB
6.5.1 Output Image Location
6.5.2 Controlling the Output Grid
6.6 Image Interpolation
6.6.1 Interpolation in Two Dimensions
6.6.2 Comparing Interpolation Methods
Bilinear Interpolation:
Refer to the image. The value at the black spot is taken using the bilinear interpolation. The value is the sum of the value at each coloured spot multiplied by the area of the rectangle of the same colour, divided by the total area of all four rectangles.
source : Wikipedia
A very good explanation on Nearest Neighbor method can be found at
http://tech-algorithm.com/articles/nearest-neighbor-image-scaling/
You can do it directly from a GUI-based environment with CVIPtools, available here:
http://cviptools.ece.siue.edu/ ; using Analysis->Geometry->Resize. You can select zero-order hold or linear interpolation.
You can obtain more details regarding implementation details in this book, Sections 3.2 and 9.6:
Digital Image Processing and Analysis: Human and Computer Vision Applications with CVIPtools, 2nd Edition, Scott E Umbaugh, CRC Press, Taylor & Francis Group, Boca Raton, FL, 2011, 956 pages, ISBN: 9781439802052
Happy Imaging!
Scott Umbaugh, Director, CVIP Laboratory, SIUE
Dear @Madhuri Panwar,
Look the links. May be usrful.
http://stackoverflow.com/questions/35196424/re-sizing-a-rectangular-image-to-a-square-image
http://www.discernmarketing.com/2011/03/how-to-make-a-rectangle-image-into-a-square-in-photoshop/
Regards, Shafagat
Matlab imresize() is very convenient to obtain whatever size you want. Please type 'help imresize' in the Matlab command window.
This extreme downsizing requires either a rather big low pass filter prior downsizing or (bi)cubic interpolation (still to be checked). (Bi)linear interpolation does interpolate withing the 4 nearest neighbors - loosing a lot of information when downsampling more than 2:1.
BTW: do you really want to distort a 3:4 image to 1:1 ?
Thank You all for responding but I want to do this on hardware so in that case I can't use it. I want to know the process of resizing it.
Please, can I ask for simple Equation to Resize an image from random size (width and Hight) into fixed size, such as 210 X 300 into 416 X 416
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