Program Working Error REGION GROWING

ERROR

Undefined function or variable 'M'.

Error in A5>regiongroww (line 36)

D = zeros(M,N);

PLEASE HELP ME IN THIS ERROR OR GIVE ME OTHER PROGRAM THAT WORKS FOR ME

THANK YOU

%% my algorithm for regiongrowing

Threshold = 15

segmentedimage = regiongroww(Image, x , y ,Threshold);

figure(3),imshow(((segmentedimage)));

function segmentedimage = regiongroww(Image, x , y ,threshold)

%[M,N]=size(Image);

%Image=Oimage(:,1:N/2);

segmentedimage = zeros(size(Image));

% 8-neighbors

nhood = [-1 -1; -1 0; -1 1; 0 -1; 0 1; 1 -1; 1 0; 1 1];

pdist = 0;

seed = Image(x,y);

reg_size = 1;

position = 0;

% some space to save co-ordinates and values of neighbors

D = zeros(M,N);

while (pdist<threshold && reg_size<numel(Image))

for ix = 1:8

% gives the co-ordinates of the 8 neighbors

xn = x + nhood(ix,1);

yn = y + nhood(ix,2);

ins=(xn>=1)&&(yn>=1)&&(xn<=M)&&(yn<=N);

if(ins&&segmentedimage(xn,yn)==0)

position = position+1;

D(position,:) = [xn yn Image(xn,yn)];

segmentedimage(xn,yn)=1;

end

end

% calculate the mean of the 8 connected pixel and and add the

% co-ordinates into x,y

dist = abs((D(1:position,3)) - (seed));

[pdist, index] = min(dist);

segmentedimage(x,y)=2; reg_size=reg_size+1;

seed= (seed*reg_size + D(index,3))/(reg_size+1);

x = D(index,1); y = D(index,2);

%delete the empty stuff

D(index,:) = D(position,:); position=position - 1;

end

segmentedimage = segmentedimage > 1;

end