CODEWITHSUNDEEP
matlabimage-processing
vikrantnegi
vikrantnegi

Reputation: 2472

Explain the code? Can compare logical and double?

f=imread('cameraman.tif');
f=im2bw(f);
[m,n]=size(f);
s1=zeros(m,2*n);
s1(1:end,1:2:end)=f(1:end,1:end);

Here is what i think the code does. We are changing s1, by comparing and replacing its element with the elements of f. s1 is a 256x512 double matrix where as f is a 256x256 logical matrix. But i don't think that's correct because after seeing and matching both the matrix i saw that not all the elements were in that fashion.

Can please someone briefly explain what does this code actually do? And how actually it done? Thanks in advance.

Upvotes: 1

Views: 102

Answers (3)

Ray
Ray

Reputation: 2508

The code has been explained well by other answer, so how about an example to give you a graphical illustration.

First, you should know by im2bw, the image is turned into black and white, meaning the image matrix is converted to 2D.

Input image:

enter image description here

Black and White image:

enter image description here

Output image:

enter image description here

Note that the third image has been augmented with zeros in even-columns. DOUBLE FAT!

Zoom in at left upper corner:

enter image description here

Upvotes: 2

hesar
hesar

Reputation: 539

f=imread('cameraman.tif');

loading file to f

 f=im2bw(f);

converting f to black and white f

[m,n]=size(f);

getting size od array (simple: image dimensions)

s1=zeros(m,2*n);

creating an array of zeros - dimension of new array is double (you can insert 2 cameraman.tif images inside s1 left and right because this is 2* columns )

s1(1:end,1:2:end)=f(1:end,1:end);

this line is a little tricky - it inserts image f into image s1 but every second line so it looks widen you can see it yourself :) just

imshow(s1);

Upvotes: 0

Chris Taylor
Chris Taylor

Reputation: 47392

These lines read an image from a file and convert it to a binary image (so that f is now a logical matrix.)

f=imread('cameraman.tif');
f=im2bw(f);

These lines create a new matrix s1 which has the same number of rows as f but twice the number of columns.

[m,n]=size(f);
s1=zeros(m,2*n);

This line fills every other column of s1 with the values of f. The result is that the odd-numbered columns (1,3,5....) in s will contain a copy of f and the even-numbered columns (2,4,6...) will be zero.

s1(1:end,1:2:end)=f(1:end,1:end);

Note that it's actually being a little verbose; you could get the same result by doing

s1(:,1:2:end) = f;

Upvotes: 4

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