I'm a new user of matlab. I want to write a code for zooming an image by a factor of 1.5 by pixel replication method.But my code takes the value of 1.5 as 1. Anyone ans me...

clc;
clear all;
close all;
b=imread('cameraman. tif) ;
figure;
imshow(b) ;title('original image') ;
[m, n, d] =size(b) ;
k=1;
l=1;
f=input('Enter the zooming factor') ;
for i=1:m
for t=1:f
for j=1:n
for t=1:f
for x=1:d
c(k,l,x)=b(i,j,x)
end
l=l+1;
end
end
l=1;
k=k+1;
end
end
figure;
imshow(c);
title('zoomed image') ;

[Dennis]

If f is 1.5 your loop will run from 1 to 1.5 in steps of 1, so there will only be 1 iteration.

[paris manoj]

Is there any possibility to zoom an image by a factor of 1.5

[Guillaume]

paris manoj comment mistakenly posted as an answer moved here:

Can I obtain the same result by nearest neighbour interpolation method

[Guillaume]

Is there any possibility to zoom an image by a factor of 1.5

Can I obtain the same result by nearest neighbour interpolation method

Of course, both can be done. imresize does it and implementing the code yourself is not particularly difficult.

[Adnan khan]

Write a complete MATLAB program for zooming an image up to 4-times of the original size (in two steps, first double, then again double

[Walter Roberson]

@Adnan khan

Okay, I've done that. Now what?

[Adnan khan]

send me in comments

[Adnan khan]

@Walter Roberson send in comments plzz

[Walter Roberson]

@Adnan khan

It is obviously a homework question. http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Answer 1

[Walter Roberson]

for t=1:f

means to start t at 1, and then each time through, add 1 to it, stopping when the value is greater than the end point, f. When f is 1.5, then that would be for t=1:1.5 . t=1 satisfies the conditions of not being greater than 1.5, so t = 1 is used. Then 1 is added to that, getting 2, and 2 is compared to 1.5 and found to be greater.

Effectively when you use an integer start and an integer increment, for t=1:f would be equivalent to for t=1:floor(f)

Also you are using the same variable names in your nested loops -- for i, then for t, then for j, then for t again. That is going to confuse the readers. But you never use t inside your loops, which is also going to confuse the readers.

Answer 2

[Florian Morsch]

Do you want to zoom into a specific area or do you just want to make you whole picture bigger or smaler? If so you can use 'imresize()' to resize your orginal image. Just get your image size with 'size()', multiply that by 1.5 and resize the image with the new size.

[Walter Roberson]

I suspect that this is an assignment to use pixel replication deliberately.

[Guillaume]

Just get your image size with 'size()', multiply that by 1.5 and resize the image with the new size

You don't need to get the image size to zoom by a factor of 1.5, you can pass the zooming factor directly to imresize.