how to write matlab code for moments?

i have this code for calculating moments function [M]= moments(I) [r c]=size(I); m=zeros(r,c); % geometric moments for i=0:1 for j=0:1 for x=1:r for y=1:c m(i+1,j+1)=m(i+1,j+1)+(x^i*y^j*I(x,y)); end end end end

xb=m(2,1)/m(1,1); yb=m(1,2)/m(1,1);

% central moments u=[ 0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 0]; for i=0:3 for j=0:3 for x=1:r for y=1:c u(i+1,j+1)=u(i+1,j+1)+(x-xb)^i*(y-yb)^j*I(x,y); end end end end

% scale invariant moments n=[ 0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 0]; for i=0:3 for j=0:3 n(i+1,j+1)=u(i+1,j+1)/(u(1,1)^(1+(i+j)/2)); end end

%rotation invariant moments I_1= n(3,1)+ n(1,3); I_2=(n(3,1)- n(1,3) )^2+ (2*n(2,2))^2; I_3=(n(4,1)-3*n(2,3))^2+ (3*n(3,2)-n(1,4))^2; I_4=(n(4,1)+n(2,3))^2+ (n(3,2)+n(1,4))^2; I_5=(n(4,1)-3*n(2,3))*(n(4,1)+n(2,3))*((n(4,1)+n(2,3))^2-3*(n(3,2)+n(1,4))^2)+(3*n(3,2)-n(1,4))*(n(3,2)+n(1,4))*(3*(n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2); I_6=(n(3,1)-n(1,3))*((n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2)+ 4*n(2,2)*(n(4,1)+n(2,3))*(n(3,2)+n(1,4)); I_7=(3*n(3,2)-n(1,4))*(n(4,1)+n(2,3))*((n(4,1)+n(2,3))^2- 3*(n(3,2)+n(1,4))^2 )- (n(1,4)-3*n(2,3))*(n(3,2)+n(1,4))*(3*(n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2);

M= [I_1 I_2 I_3 I_4 I_5 I_6 I_7];

but it gives same values for all images is this correct way to calculate moments?

Answer 1

[Iman Ansari]

You may need to convert your input image to double. In uint8 numbers greater than 255 became 255.

function [M]= moments(I)
I=double(I);
[r c]=size(I); 
m=zeros(r,c); 
% geometric moments 
for i=0:1 
    for j=0:1 
        for x=1:r 
            for y=1:c 
                m(i+1,j+1)=m(i+1,j+1)+(x^i*y^j*I(x,y)); 
            end
        end
    end
end

xb=m(2,1)/m(1,1); 
yb=m(1,2)/m(1,1);

% central moments 
u=[ 0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 0]; 
for i=0:3 
    for j=0:3 
        for x=1:r 
            for y=1:c 
                u(i+1,j+1)=u(i+1,j+1)+(x-xb)^i*(y-yb)^j*I(x,y); 
            end
        end
    end
end

% scale invariant moments 
n=[ 0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 0]; 
for i=0:3 
    for j=0:3 
        n(i+1,j+1)=u(i+1,j+1)/(u(1,1)^(1+(i+j)/2)); 
    end
end

%rotation invariant moments 
I_1= n(3,1)+ n(1,3); 
I_2=(n(3,1)- n(1,3) )^2+ (2*n(2,2))^2; 
I_3=(n(4,1)-3*n(2,3))^2+ (3*n(3,2)-n(1,4))^2; 
I_4=(n(4,1)+n(2,3))^2+ (n(3,2)+n(1,4))^2; 
I_5=(n(4,1)-3*n(2,3))*(n(4,1)+n(2,3))*((n(4,1)+n(2,3))^2-3*(n(3,2)+n(1,4))^2)...
    +(3*n(3,2)-n(1,4))*(n(3,2)+n(1,4))*(3*(n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2); 
I_6=(n(3,1)-n(1,3))*((n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2)+ 4*n(2,2)*(n(4,1)...
    +n(2,3))*(n(3,2)+n(1,4)); 
I_7=(3*n(3,2)-n(1,4))*(n(4,1)+n(2,3))*((n(4,1)+n(2,3))^2- 3*(n(3,2)+n(1,4))^2 )...
    - (n(1,4)-3*n(2,3))*(n(3,2)+n(1,4))*(3*(n(4,1)+n(2,3))^2-(n(3,2)+n(1,4))^2);

M= [I_1 I_2 I_3 I_4 I_5 I_6 I_7];

[Sachin]

thnx a lot iman

[fateme]

thanks

[Ricki Chindra]

Iman how to call the function? I'm trying it, no error but when I run it, There is no image in the figure

[Akshit Vekariya]

will this code work on moment invariant...?

[Sparsh Garg]

I am getting error Function definitions are not permitted in this context. please explain how to solve this error