Add Poisson Noise in an image

I have an image in JPEG format. I want to add Poisson noise in the image.

>> a=imread('pattern2.jpg');

>> J =imnoise(a,'poisson');

>> figure(4); imshow(J)

But in output there is no image. showing error

?? Error using ==> imnoise Unknown noise type.

==> J =imnoise(a,'poisson');

someone help

With Regards

-Abhijit Das

Answer 1

[Wayne King]

Hi Abhijit, Are you sure that you are using the MathWorks' imnoise function? Perhaps you have another imnoise.m function that precedes the MathWorks' version on your path.

Enter:

>>which imnoise

Do you get a path returned like (ending in):

matlab\toolbox\images\images\imnoise.m

If not, then either remove the path to the non-MathWorks' imnoise with rmpath, or move the non-MathWorks' imnoise out of the MATLAB search path.

[Abhijit Das]

I have tested the other noises such as Gaussian, salt & pepper etc. These types of noises are being added to the image. If you can explain with example that will be better.

-Thanking You

Abhijit Das

[Wayne King]

If you can tell us what

>>which imnoise

returns and what version of MATLAB you are using, that would be helpful.

Answer 2

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/13619-toolbox-non-local-means/content/toolbox_nlmeans/toolbox/imnoise.m

if you need to.

poisson noise was new as of MATLAB R12+, Image Processing Toolbox version 3.0. That version of MATLAB appears to be a second release of MATLAB 6.0 but that predates MATLAB 6.1. If you have Image Processing Toolbox 2.2 with MATLAB 6.0, you are perhaps eligible for a free upgrade to toolbox version 3.0; see <http://www.mathworks.com/support/solutions/en/data/1-18WGT/index.html?product=IP&solution=1-18WGT>

[Devi Anu]

can anyone tell me how to add mixed noise in HSI data??THANKS IN ADVANCE....