How to get the both uncontiguous objects in an image as just an object
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Bachtiar Muhammad Lubis on 20 Dec 2018
i want to loop a word in image, so that i can take every character in that image. but if i use the third dimension of bwlabel as my limit loop, the character like "i" will assume as 2 characters. because it has 2 uncontiguous object in that image. i think i have found how to get all characters of "Nick" by cropped those character automatically. but i confuse how to loop it so i can take every character and compare them with my training data.
Image Analyst on 23 Dec 2018
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
fontSize = 20;
% Show image
h1 = subplot(4, 12, 1:12);
title('INPUT IMAGE WITH NOISE')
%% Convert to gray scale
if size(grayImage, 3) == 3 % RGB image
%% Convert to binary image
threshold = graythresh(grayImage);
binaryImage = im2bw(grayImage, threshold);
% Remove all object containing fewer than 15 pixels
binaryImage = bwareaopen(binaryImage,15);
axis('image', 'on'); % Display tick marks.
title('Binary Image', 'FontSize', fontSize);
% Find horizontal profile
h2 = subplot(4, 12, 13:24);
horizontalProfile = sum(binaryImage, 1);
title('Horizontal Profile', 'FontSize', fontSize);
% Find dividing lines between the characters.
props = regionprops(horizontalProfile == 0, 'Centroid');
xyCentroids = [props.Centroid];
dividingLines = xyCentroids(1:2:end)
for k = 1 : length(dividingLines)
thisX = dividingLines(k);
line(h1, [thisX, thisX], ylim(h1), 'Color', 'r');
line(h2, [thisX, thisX], ylim(h2), 'Color', 'r');
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'Outerposition', [0, 0.05, 1, 0.95]);
% Extract each letter.
fontSize = 12;
for k = 1 : length(dividingLines) - 1
thisX = round(dividingLines(k));
nextX = round(dividingLines(k+1));
subplot(4, 12, 24 + k);
thisLetter = binaryImage(:, thisX:nextX);
caption = sprintf('Letter #%d', k);
title(caption, 'FontSize', fontSize);
Note that if you have kerning, like with characters 3 and 5, this algorithm won't work and you will have to do a little more work, like label the sub image and if there are two blobs, find their centroids. If there centroids are horizontally separated, then they're two kerned characters and you can nsplit them apart with ismember(). If the centroids are vertically aligned or close to it, then you might consider it as one character that has two parts like an i or j.