how to get an vertical histogram of an binary image and based on that histogram segment words from a row

Question

suppose i have an image in which there are some letters.based on those letters of the image i want to show the vertical projections of histogram of the given image in an a

Answer 1

First of all, you are not looking for a "vertical histogram", but rather a bar plot of vertical sum.

Here's a simplified example.

Consider this input image

You can read and threshold it

img = imread('http://i.stack.imgur.com/3YonG.png')
bw = img(:,:,1)<128;  %// convert to binary, text = 1

Now you can inspect the vertical sum

sc = sum(bw,1);  %// sum columns
figure;bar(sc);  

As you can see if there are more than ~2 pixels set in a column - this is probably a letter. We can use this threshold

rm = sc > 2; 
cs = cumsum(~rm).*rm;  %// assign unique value to each "letter" columns
mask = bsxfun(@times, bw, cs );  %// seperate the letters in the mask

Resulting with