how to get horizontal projection of histogram of an binary image ?and based on that how to segment of each line in the image? please suggest me

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ayushi
ayushi on 18 May 2016
Commented: ayushi on 21 May 2016
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>> this is my ZjSqKcW.jpg and on the bases of this image i want the horizontal projection of histogram like g.png and after the histogram i want the segmentation of each line.how to do please suggest

Accepted Answer

Alessandro Masullo
Alessandro Masullo on 20 May 2016
Given your image im, you can binarize it with im2bw:
bw = 1-im2bw(image);
The horizontal histogram (I guess) is the sum of the object in the horizontal direction, which is
h = sum(bw,2)
You can then plot it with:
figure
plot(sum(bw,2),1:size(bw,1))
Which gives you the image attached.
The segmentation could be performed with findpeaks.
  5 Comments
ayushi
ayushi on 21 May 2016
sir will you please explain it with the help of example i tried the following code but its not working properly and also i am not able to detect where is the error in this:
%DESKEWING
% Find the coordinates of all the pixels
[y, x] = find(Iedge2);
% Fit them to a line
coefficients = polyfit(x, y, 1);
% Get a line from the left to the right
xEnds = [1, columns];
yEnds = polyval(coefficients, xEnds);
hold on;
line(xEnds, yEnds, 'Color', 'r');
% Get the angle
angle = atand((yEnds(2) - yEnds(1)) / (xEnds(2) - xEnds(1)));
rotatedImage = imrotate(Iedge2, angle);
% Display the rotated image.
subplot(2, 2, 4);
imshow(rotatedImage, [],'Parent',handles.axes2);
title('Binary Image', 'FontSize', 10);
%regionprops to get all the BoundingBoxes form your lines
stats=regionprops(rotatedImage,'BoundingBox');
figure, imshow(rotatedImage)
BoundingBoxes=struct2cell(stats);
BoundingBoxes=cell2mat(BoundingBoxes'); % making it into an array
[~,ind]=sort(BoundingBoxes(:,2)); % sorting it to y
BoundingBoxes=BoundingBoxes(ind,:); % apply the sorted vector
lineNr=8;
imshow(original(BoundingBoxes(2,lineNr):...
BoundingBoxes(2,lineNr)+BoundingBoxes(4,lineNr),...
BoundingBoxes(1,lineNr):BoundingBoxes(1,lineNr)+BoundingBoxes(3,lineNr) ))

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