Forums

Color Images

Started by aditya October 31, 2003
Hi All,
I was trying to isolate the RGB components from a
given image.I wrote the following code and i am
getting the red and blue components but for the green
component i am getting a Black image.Can some one
guide what is going wrong.Also when i try to take the
histogram of the image using Imhist i have a problem
because its a JPEG image.can anyone tell me how to
over come it.
Thanks in Advance.
Regards,
Aditya

close all
clear all
A=imread('images.jpg');
B=double(A);
redimage=A;
redimage(:,:,2:3)=0;
figure(1)
title('red image')
imagesc(redimage)
blueimage=A;
blueimage(:,:,1:2)=0;
figure(2)
title('blueimage')
greenimage=A;
greenimage(:,:,1:3)=0;
figure(3)
title('greenimage')

__________________________________



Try this code ....

close all
clear all
A=imread('images.jpg');
B=double(A);
redimage=A;
redimage=A(:,:,1);
figure(1);itle('red image')
imagesc(redimage)
blueimage=A;
blueimage=A(:,:,3);
figure(2)
&title('blueimage')
greenimage=A;
greenimage=A(:,:,2);
figure(3)
title('greenimage')

> Hi All,
> I was trying to isolate the RGB components from a
> given image.I wrote the following code and i am
> getting the red and blue components but for the green
> component i am getting a Black image.Can some one
> guide what is going wrong.Also when i try to take the
> histogram of the image using Imhist i have a problem
> because its a JPEG image.can  anyone tell me how to
> over come it.
> Thanks in Advance.
> Regards,
> Aditya >
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hi aditya,
you are getting a black image because,
1:3 in greenimage(:,:,1:3)= 0; means that all values
with third dimension from 1 to 3 should be made zero.
hence the above statement makes the matrix greenimage
a zero matrix, which represents a black image.
hence to extract the green component one way is,
greenimage(:,:,1) = 0;
greenimage(:,:,3) = 0;

hope this solves your problem.
- Harish --- aditya <> wrote:
---------------------------------
Hi All,
I was trying to isolate the RGB components from a
given image.I wrote the following code and i am
getting the red and blue components but for the green
component i am getting a Black image.Can some one
guide what is going wrong.Also when i try to take the
histogram of the image using Imhist i have a problem
because its a JPEG image.can anyone tell me how to
over come it.
Thanks in Advance.
Regards,
Aditya

close all
clear all
A=imread('images.jpg');
B=double(A);
redimage=A;
redimage(:,:,2:3)=0;
figure(1)
title('red image')
imagesc(redimage)
blueimage=A;
blueimage(:,:,1:2)=0;
figure(2)
title('blueimage')
greenimage=A;
greenimage(:,:,1:3)=0;
figure(3)
title('greenimage')

__________________________________

_____________________________________
Note: If you do a simple "reply" with your email
client, only the author of this message will receive
your answer. You need to do a "reply all" if you want
your answer to be distributed to the entire group.

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About this discussion group:

To Join:

To Post:

To Leave:

Archives: http://www.yahoogroups.com/group/matlab

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http://www.dsprelated.com/groups.php3
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> greenimage(:,:,1:3)=0;

you should use 'greenimage(:,:,[1,3])' in the above
line. 1:3 is 1,2,3.

Navan.

--- aditya <> wrote:
> Hi All,
> I was trying to isolate the RGB components from a
> given image.I wrote the following code and i am
> getting the red and blue components but for the
> green
> component i am getting a Black image.Can some one
> guide what is going wrong.Also when i try to take
> the
> histogram of the image using Imhist i have a problem
> because its a JPEG image.can anyone tell me how to
> over come it.
> Thanks in Advance.
> Regards,
> Aditya >
>
> close all
> clear all
> A=imread('images.jpg');
> B=double(A);
> redimage=A;
> redimage(:,:,2:3)=0;
> figure(1)
> title('red image')
> imagesc(redimage)
> blueimage=A;
> blueimage(:,:,1:2)=0;
> figure(2)
> title('blueimage')
> greenimage=A;
> greenimage(:,:,1:3)=0;
> figure(3)
> title('greenimage')


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