After finding lines, how to find squares in an Image of a chessboard?

Hello, I'm trying to detect the squares of a chessboard and name them accordingly (H8, A6, C4 etc.). I have already found the lines in the chessboard. Here is my code:

EDIT: Do you believe that there might be a way to use the lines, so I can find the squares of the chess?

if true
  clear all; clc; close all;

I = imread('chess.jpg');

th = [0 0.417]; %threshold for canny
s = sqrt(3); %sigma for canny
Ig = rgb2gray(I);
B = edge(Ig,'Canny',th,s); %Using canny in Graythresh image

 %Hough Transformation

 [H, theta, rho] = hough(B, 'RhoResolution',0.9,'ThetaResolution',0.09);

 peaks  = houghpeaks(H,19,'threshold',ceil(0.3*max(H(:)))); %wiki
 %Finding Lines
 lines = houghlines(B, theta, rho, peaks, 'FillGap', 350, 'MinLength', 20);

 figure(2)
 imshow(I)

 hold on

 maxLength = 0;
%Show lines
for i = 1 : length(lines)
    xy = [lines(i).point1; lines(i).point2];

    % LineSHow
    plot( xy(:, 1), xy(:, 2), 'LineWidth', 2, 'Color', 'green' );

    % Length of line
    lengthOfLines(i) = norm(lines(i).point1 - lines(i).point2);

    % Find angle
    angles(i) = lines(i).theta;

    % Check if this is the longest line
    if ( lengthOfLines > maxLength )
        maxLength = lengthOfLines;
        xyLongest = xy;
    end
end
 %Below, is a failed try to find the squares, using a suggestion by another post 
 %about finding squares
 BW = im2bw(Ig);
 S = regionprops(peaks, 'BoundingBox', 'Centroid');
 imshow(I); hold on;
for cnt = 1 : numel(S)
    bb = S(cnt).BoundingBox;
    rectangle('position',bb,'edgecolor','r','linewidth',2);
end
  end

This is the image:

This is the line detection:

[KAE]

Shouldn't it be

S = regionprops(BW, 'BoundingBox', 'Centroid');

Answer 1

[mohammad nemat]

hi,i ran this code with this picture but i didn't get this result with detected line.

what is this problem and why i can't get this output?