How to get the both uncontiguous objects in an image as just an object

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Bachtiar Muhammad Lubis 2018-12-20

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https://ww2.mathworks.cn/matlabcentral/answers/436707-how-to-get-the-both-uncontiguous-objects-in-an-image-as-just-an-object

评论： Bachtiar Muhammad Lubis 2019-1-3

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.

Thanks before.

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Bachtiar Muhammad Lubis 2018-12-23

i pologize for didn't attach the code and testing image before. and also i apologize because my slow response, because i haven't gotten any notification yet in mail.

Here the files are.

the "i" as my example case in above is the ninth character from the left in Adok_karo1_biner.jpg.

thanks for your respone @Image Analyst

Image Analyst 2018-12-23

Why are you doing edge detection and dilation??? That certainly doesn't make it easier to separate the characters. Don't do that!

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Answer 1

Image Analyst 2018-12-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/436707-how-to-get-the-both-uncontiguous-objects-in-an-image-as-just-an-object#answer_353684

在 MATLAB Online 中打开

Try this:

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;
format compact;
fontSize = 20;
grayImage =imread('Adok_karo1_biner.jpg');
% Show image
figure(1)
h1 = subplot(4, 12, 1:12);
imshow(grayImage);
impixelinfo
title('INPUT IMAGE WITH NOISE')
%% Convert to gray scale
if size(grayImage, 3) == 3 % RGB image
	grayImage=rgb2gray(grayImage);
end
%% Convert to binary image
threshold = graythresh(grayImage);
binaryImage = im2bw(grayImage, threshold);
% Remove all object containing fewer than 15 pixels
binaryImage = bwareaopen(binaryImage,15);
imshow(binaryImage);
axis('image', 'on'); % Display tick marks.
title('Binary Image', 'FontSize', fontSize);
% Find horizontal profile
h2 = subplot(4, 12, 13:24);
horizontalProfile = sum(binaryImage, 1);
plot(horizontalProfile, 'b-');
title('Horizontal Profile', 'FontSize', fontSize);
grid on;
% 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');
end
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'Outerposition', [0, 0.05, 1, 0.95]);
drawnow;
% 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);
	imshow(thisLetter);
	caption = sprintf('Letter #%d', k);
	title(caption, 'FontSize', fontSize);
end
	

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.

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Bachtiar Muhammad Lubis 2018-12-25

thank you for your respone sir.

The charater 7 of cropped characters actually is

instead of

sir. this character is the one pf my biggest problem sir, i can't use bwlabel for identify all characters in the document because of this character.

And then the character 11. I'd tried opening to separate those object (input is a document), but didnt work, because when i use opening this character is succesfully separated, but another character got effect as well, whichs is an object was seperated into two objects. But if i do opening when on the cropped characters, i guess, i can't solve character 3 and 5, because they are in a process.

for the first problem i guess i've found how to solve it by finding the gapses (spaces) horizontally to find the line and then vertically to find the character. But there is a problem in my tes2_2.m file. First ran this file worked properly (i guess). but if i ran it once again this code didn't show any input at all, and the process couldn't terminate by me. So that i forced close my matlab application.

would you help me sir, please.

i've attached my files.

Image Analyst 2018-12-30

在 MATLAB Online 中打开

You should use ismember() as I showed in my Image Segmentation Tutorial in my File Exchange:

L1 = ismember(L, 1);
L2 = ismember(L, 2);

because I think find() may just return a 1-D array of linear indexes, not an image.

Bachtiar Muhammad Lubis 2019-1-3

thank you Image Analyst it worked perfectly. do you wanna help me to answer my new question sir. the question related with this question. This the link is :

https://www.mathworks.com/matlabcentral/answers/438097-how-to-refresh-subplot-whenever-it-is-called-in-loop-iteration.

thanks a lot sir.

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How to get the both uncontiguous objects in an image as just an object

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