how to plot the histogram of the segmented line of document images - matlab

Question

I am writing a program for line segmentation and I want to plot a horizontal histogram of the input image and the segmented lines, but I don't know the code for plotting histograms. Please help me, I have given my program below:
close all;
clear all;
clc;
im=imread('test_img.tif');%read the image
figure, imshow(im);
title('INPUT IMAGE WITH NOISE');
area(im)
if size(im,3)==3 % RGB image %% Convert to gray scale
im=rgb2gray(im);
end
threshold = graythresh(im); %% Convert to binary image
im =~im2bw(im,threshold);
im = bwareaopen(im,15); %% Remove all object containing fewer than 60 pixels
figure(2) %% Show image binary image
imshow(~im);
title('INPUT IMAGE WITHOUT NOISE')
%find Area of Interest:
a=(~im);
ijk=~a;
xy=sum(ijk,2);
measurements = regionprops(xy == 0, 'Area', 'PixelIdxList');
% Get indexes of those regions that are >= 20 in length.
fiveLongRegions = find([measurements.Area] >= 5);
theIndexes = vertcat(measurements(fiveLongRegions).PixelIdxList);
c=a;
c(theIndexes,:)=0;
figure, imshow(c);
title('AREA OF INTEREST FOR LINE SEGMENT');
%Segmentation of line:
[x,y]=size(a);
mat1=sum(a,2);%sum the elements of bwrowise and save into column matrix mat1
mat2=y-mat1;%subtract each element of the sum matrix(mat1) from the width length(no. of columns)
mat3=mat2~=0;
mat4=diff(mat3);
index1=find(mat4);
[q,w]=size(index1);%size of index2 matrix is q*w
kap=1;
lam=1;
%iii=1;
%ii=1;
while kap<((q/2)+1);%number of loops=number of lines
k=1;
mat5=([]);
for j=(index1(lam)+1):1:index1(lam+1)
mat5(k,:)=a(j,:); %store the line segmented matrix
k=k+1;
end
lam=lam+2;
kap=kap+1;
figure, imshow(mat5);
imsave();
end