find 8 neighbours in image

hi dears..... plz help me

how i find the 8 neighbours around the white pixels...

[Walter Roberson]

Find them in what sense? What output are you looking for?

[RASHMI CHINNAPPA]

how to find the 8 neighbours around a single white region

[Image Analyst]

Use imdilate() then and it with the original

neighbors = imdilate(bw, true(3)) & ~bw;

Answer 1

[KSSV]

Read about knnsearch

I = imread('2.png') ;
I = rgb2gray(I) ;
[y,x] = find(I) ;
% 8 nearest neighbors
[ny,nx] = size(I) ;
[X,Y] = meshgrid(1:nx,1:ny) ;
% global indices
idx = knnsearch([X(:) Y(:)],[x,y],'k',8) ;
% sub indices 
[i,j] = ind2sub(size(I),idx) ;

[Sajid Rahim]

clear all;

[filename 
pathname]=uigetfile('*.jpg;*.png;*.tif;*.tiff;*.gif;*.bmp;');

inputimage=imread([pathname filename]);

I=inputimage;

% I = imread('5.png') ;

I = rgb2gray(I) ;

[y,x] = find(I) ;

figure

imshow(I)

hold on

plot(x,y,'.b')

% x

% y

% z=(y+x)/2

% plot(z,'.r')

a=x(1)

b=y(1)

plot(x(1),y(1),'*y')

plot(x(end),y(end),'*y')

% neighbors(1) = (a,b-1);

neighbors(1) = I(a,b-1);

plot(a,b-1,'*r')

neighbors(2) = I(a,b+1);

plot(a,b+1,'*r')

neighbors(3) = I(a,b+2);

plot(a,b+2,'*r')

neighbors(4) = I(a+1,b);

plot(a+1,b,'*r')

neighbors(5) = I(a+1,b+1);

plot(a+1,b+1,'*r')

neighbors(6) = I(a+2,b+2);

plot(a+2,b+2,'*r')

neighbors(7) = I(a+2,b);

plot(a+2,b,'*r')

neighbors(8) = I(a+2,b+1);

plot(a+2,b+1,'*r')

neighbors(9) = I(a+2,b+2);

plot(a+2,b+2,'*r')

this is my code i done it

but now i wana to find each 8 neighbers of every finded neibgher

[Walter Roberson]

This code does not answer the questions "Find them in what sense? What output are you looking for?"

Answer 2

[Mehadi Hasan]

I = imread('2.png') ;

I = rgb2gray(I) ;

[y,x] = find(I) ;

% 8 nearest neighbors

[ny,nx] = size(I) ;

[X,Y] = meshgrid(1:1x,1:1y) ;

% global indices

idx = knnsearch([X(:1) Y(:1)],[x,y],'k',8) ;

% sub indices

[i,j] = ind2sub(size(I),idx) ;