how to calculat the sum of pixel vaules inside a particular region

hai

i am studing about localization of the optic disc

here i have to define two feature maps namely

                 1.vertical map
                 2. horizontal map

i have completed that

my second step is to define a rectangular window of width=30 and height=image height in vertical map

third step is two move the window from left to right and calculate the sum of pixel values inside the rectangular region in the vertical map

as i can't find a function to move the rectangle of specified height and width and then calculating the sum i have used the following code for calculating the sum

but i am getting the error as index exceeds matrix dimension and this is my error please help me

[width, height] = size(final2);
count=20;
inc1=1;
k=0;
  for k=1:count
   sum(k)=0;
  end

a=1;
b=30;
while(inc1 < count-1)
for i=1:700
    for j=a:b
      sum(inc1)=sum(inc1)+final2(j,i);
    end
    a=a+30;
    b=b+30;
end
i =inc1+1;
end

thanks

Answer 1

[Andrei Bobrov]

variant 1

final2 = randi([2 25],5,25);
b = 5;
[width, height] = size(final2);
sum1 = squeeze(sum(reshape(final2,width,b,[]),2))

variant 2

idl = cumsum([1:b; b*ones(fix(height/b)-1,b)]);
sum1 = cell2mat(arrayfun(@(i1)sum(final2(:,idl(i1,:)),2),1:size(idl,1),'un',0));

more variant with use function from Image Processing Toolbox - blockproc

sum2 = blockproc(final2,[width b],@(block_struct) sum(block_struct.data,2))