How can I decide if it's dark or bright (barcode in image)

Hey,

I'm doing a project and I have a problem, I have this picture and I need to figure from it a 8X8 barcode of dark (black) and bright (white), here is the picture:

I tried to do median of each block but the values look similar.

Thanks.

Answer 1

[Image Analyst]

Use blockproc to perform the mean of each block. After that you need to threshold to decide whether a block if bright or dark.

% Demo code to divide the image up into an 8 by 8 grid
% and replace each pixel in the block by the mean,
% of all the gray levels of the pixels in the block.
%
clc;
clearvars;
close all;
workspace;
fontSize = 16;

% Read in a standard MATLAB gray scale demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
if ~exist(folder, 'dir')
  % If that folder does not exist, don't use a folder
  % and hope it can find the image on the search path.
  folder = [];
end
baseFileName = 'cameraman.tif';
fullFileName = fullfile(folder, baseFileName);
grayImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 1.
[rows, columns, numberOfColorBands] = size(grayImage)
% Display the original gray scale image.
subplot(2, 1, 1);
imshow(grayImage, []);
axis on;
caption = sprintf('Original Gray Scale Image\n%d rows by %d columns', ...
  rows, columns);
title(caption, 'FontSize', fontSize);

% Enlarge figure to full screen.
set(gcf, 'Position', get(0,'Screensize')); 
set(gcf,'name','Image Analysis Demo','numbertitle','off') 

% Block process the image to replace every pixel in the 
% 8 pixel by 8 pixel block by the mean of the pixels in the block.
% The image is 256 pixels across which will give 256/8 = 32 pixel by 32 pixel blocks.
meanFilterFunction = @(theBlockStructure) mean2(theBlockStructure.data(:));
blockSizeRows = floor(rows/8);
blockSizeCols = floor(columns/8);
blockSize = [blockSizeRows, blockSizeCols]
blockyImage32 = blockproc(grayImage, blockSize, meanFilterFunction);
[rowsOut, columnsOut] = size(blockyImage32);

% Display the block mean image.
subplot(2, 1, 2);
imshow(blockyImage32, []);
axis on;
grid on;
caption = sprintf('Block Mean Image\nInput block size = %d rows by %d columns\n%d rows by %d columns', ...
  blockSizeRows, blockSizeCols, rowsOut, columnsOut);
title(caption, 'FontSize', fontSize);