Exceed array bound at position 2

Hi guys, I am trying to calculate the matrix moments for a binary image, however I encountered the following error:

>> run_A_2

Index in position 2 exceeds array bounds. Index must not exceed 438.

Error in features_2 (line 35)

m01 = m01 + j * Iin(i,j) / 255;

Error in run_A_2 (line 6)

[P, A, C, xbar, ybar, phione] = features_2(I1);

Here is my code:

function [P, A, C, xbar, ybar, phione] = features_2(Iin)
    %perimeter
    P = sum(sum(bwperim(Iin)==1));     %bwperim returns the perimeter 
                                       %by calculating the distance between 
                                       %each adjoining pair of pixels around 
                                       %the border of the binary image.

    %area
    A = sum(sum(Iin == 255)); %summing the number of pixel that are white

    %compactness
    C = P^2/(4 * pi * A);

    %centroid
    [rows cols] = size(Iin);

    m00 = A;
    m10 = 0;
    m01 = 0;

    %calculating m10
    for i = 1:rows
        for j = 1:cols
            m10 = m10 + j * Iin(i,j) / 255;
        end
    end
    
    %calculating m01
    for i = 1:cols
        for j = 1:rows
            m01 = m01 + j * Iin(i,j) / 255;
        end
    end


    xbar = m10 / m00; %m10/m00
    ybar = m01 / m00; %m01/m00

May I know what is the issue?

Thanks!

Answer 1

[Askic V]

This is your problem:

 for i = 1:cols
        for j = 1:rows
            m01 = m01 + j * Iin(i,j) / 255;
        end
    end

you mixed columns and rows comparing to the previous for loop

[Miles Hao Peng Su]

Ohh I see! Here is my improved code:

    for i = 1:rows
        m10 = m10 + i * sum(Iin(i,:) / 255);
    end

It works fine now! Thank you!