function [ s ] = filtracja( image, mask )

    org = image(:,:,1);
    f = mask;
    [xx, yy] = size(org);
    a = [org(1,1), org(1,:), org(1,yy); org(:,1), org(:,:), org(:,yy); org(xx,1), org(xx,:), org(xx,yy)];
    a = double(a);
    [x,y] = size(a);
    s = zeros(x,y);

    if numel(mask) == 9
        for i=2:x-1
            for j=2:y-1
                s(i,j)=f(1,1)*a(i-1,j-1)+f(2,1)*a(i,j-1)+f(3,1)*a(i+1,j-1)+f(1,2)*a(i-1,j)+f(2,2)*a(i,j)+f(3,2)*a(i+1,j)+f(1,3)*a(i-1,j+1)+f(2,3)*a(i,j+1)+f(3,3)*a(i+1,j+1);
            end
        end

    elseif numel(mask) == 4
        for i=2:x
            for j=2:y
                s(i,j)=f(1,1)*a(i-1,j-1)+f(2,1)*a(i,j-1)+f(1,2)*a(i-1,j)+f(2,2)*a(i,j);
            end
        end
    end
    s = s(2:x-1,2:y-1);
    s = fix(s);
end