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MATLAB PROGRAM : 2D MEDIAN FILTERING FOR SALT AND PEPPER NOISE WITHOUT USING medfilt2 FUNCTION

MEDIAN FILTER:

In digital Image processing, removing the noise is one of the preprocessing techniques.
The image noise may be termed as random variation of brightness or color information.
There are various types of image noise. Here a matlab program to remove 'salt and pepper noise' using median filtering is given.
 The random occurrence of black and white pixels is ‘salt and pepper noise’.

The procedural steps for 2D median filtering:


Learn how to pad with zeros using MATLAB built_in function padarray.

FLOW CHART:


MATLAB CODE:

%READ AN 2D IMAGE
A=imread('zebra.jpg');
title('IMAGE WITH SALT AND PEPPER NOISE');
figure,imshow(A);

%PAD THE MATRIX WITH ZEROS ON ALL SIDES
modifyA=zeros(size(A)+2);
B=zeros(size(A));

%COPY THE ORIGINAL IMAGE MATRIX TO THE PADDED MATRIX
        for x=1:size(A,1)
            for y=1:size(A,2)
                modifyA(x+1,y+1)=A(x,y);
            end
        end
      %LET THE WINDOW BE AN ARRAY
      %STORE THE 3-by-3 NEIGHBOUR VALUES IN THE ARRAY
      %SORT AND FIND THE MIDDLE ELEMENT
       
for i= 1:size(modifyA,1)-2
    for j=1:size(modifyA,2)-2
        window=zeros(9,1);
        inc=1;
        for x=1:3
            for y=1:3
                window(inc)=modifyA(i+x-1,j+y-1);
                inc=inc+1;
            end
        end
       
        med=sort(window);
        %PLACE THE MEDIAN ELEMENT IN THE OUTPUT MATRIX
        B(i,j)=med(5);
       
    end
end
%CONVERT THE OUTPUT MATRIX TO 0-255 RANGE IMAGE TYPE
B=uint8(B);
title('IMAGE AFTER MEDIAN FILTERING');
figure,imshow(B);












Learn how to add 'salt and pepper noise to an image'.Median filtering preserves the image without getting blurred. Median filtering is done on an image matrix by   finding the median of the neighborhood pixels by using a window that slides pixel by pixel.


  


    ALSO MEDIAN FILTER FOR RGB IMAGE
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43 comments:

Anonymous said... Reply to comment

thank you so much for project lol

jeena said... Reply to comment

thanks a lot for this code

punya said... Reply to comment

great, thankx a lot, wht can i say, amazing

pooja said... Reply to comment

thanks for this helpful code...

annah said... Reply to comment

thank you..it helps alot.. :)

HANEE said... Reply to comment

great job but why is my image become red after the MEDIAN FILTERING???

Aaron Angel said... Reply to comment

@HANEE

Kindly check whether the image is 2D or RGB image. If the image is RGB then convert it into grayscale and proceed.

HANEE said... Reply to comment

it worked perfectly with Gaussian Filter but not with Median Filter(image becomes red), i'm now trying with other images to see whether it is a image problem or what..

Unknown said... Reply to comment

thanks for this usefull code........
can we selection direction in a window ? if yes how is it possible ? actually i m thinking to preserve edges of image.......

Unknown said... Reply to comment

thanks

Unknown said... Reply to comment

I ve a problem with the Median Filter. The image becomes red.
Somebody can help me with this problem?

Unknown said... Reply to comment

I ve also the problem that the picture becomes red with the Median Filter . Can somebody help? Thank you a lot

Unknown said... Reply to comment


Do you have also an Matlab Code for the Gauss filter?

I didn t find / see one
Thanks

regrads,

CHristian

Unknown said... Reply to comment

thanks. this is really helpful

Unknown said... Reply to comment

whether any functions will change wen v change the version of matlab

Unknown said... Reply to comment

hi can you give the same code for fuzzy median filter pa

Unknown said... Reply to comment

nice work

Unknown said... Reply to comment

Can someone code for Wiener Filter please for gray scale image

Unknown said... Reply to comment

I ve also the problem that the picture becomes red with the Median Filter . Can somebody help? Thank you a lot

Aaron Angel said... Reply to comment

@Janardhan Mopada

Is your input Image RGB? if so, convert it to grayscale and proceed.

kassambe said... Reply to comment

do you have a code for contour detection with many algorithm?

tememe said... Reply to comment

thank you very useful

New Staff said... Reply to comment

Anybody can provide me the code of the 'Noise Reduction By Fuzzy Image Filtering''.

waiyannn said... Reply to comment

Sir, Let me know the code of Tri colour Filter(Image) / RGB only

Unknown said... Reply to comment

median filtering will be work on syntax "medfilt2(gray scale image)"

ajay said... Reply to comment

Sir how to Mean filtering can apply on the DN (digital no.) values
of each pixel vector so as to smoothen out the SRC (spectral response curve) of a pixel for hyperspectral data?

Isa Bastos said... Reply to comment

Use rgb2gray and it will work fine!

Unknown said... Reply to comment

thanks

Unknown said... Reply to comment

what about average filter?

safak said... Reply to comment

how to adapt thıs to 9*9 or 13*13 medıan fılter ? how ı do ıt?

safak said... Reply to comment

how ı adapt matlab code to 9*9 or 13*13 medıan fılter ?

Unknown said... Reply to comment

For rgb you need to separate 3 plates red, green, blue and aply median filtering on each plane.
And atlast combine them using cat function.

Unknown said... Reply to comment

thank you sir

Unknown said... Reply to comment

Awesome. Do you have the code for Average filtering also?

Unknown said... Reply to comment

awesome. do you have the code for average filtering also?

Unknown said... Reply to comment

Thanks for this helpful code

Unknown said... Reply to comment

the image turned red. there is some problem kindly rectify.

Aaron Angel said... Reply to comment

@AASTHA SINGH
The code is for grayscale image. Kindly check whether it is rgb or grayscale.

Unknown said... Reply to comment

can i use this median filter code to remove noise from ultrasound image????? plsss reply

Unknown said... Reply to comment

How would i change this for a 7x7 median filter?

Raffay said... Reply to comment

What is the meaning of med and med(5). Idk what that means and ive been scratchig my head for the past 1 hr

Anisha said... Reply to comment

thank you, really helpful

Unknown said... Reply to comment

How to change this for a 7x7 or 5x5 neighborhood ?

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