What is histogram? How low brightness and high brightness images can be identified from a histogram? DIP


The histogram plots the number of pixels in the image (vertical axis) with a particular brightness value (horizontal axis). Considering the following graph,

Here the vertical axis is showing the no of pixels and horizontal axis is showing the grey-levels of the image. From this histogram of that image it is found that the image contains 75 pixels of 180 grey-level, 100 pixels of 100 grey-levels and 175 pixels of 130 grey-levels. 

So in that way, histogram works and it is used. 

Identifying High and Low Brightness Using Histogram: 

Using a histogram it is very easy to identify the high and low brightness of an image. We can know the specific number of pixels containing specific grey-levels. We also know that 0 grey-level for black and 255 grey-level is for white. So if we find maximum pixels containing higher grey-levels then it can be said that the image is of high brightness and if maximum pixels containing lower grey-levels then it can be said that the image is of low brightness.  

Author: Tanmay Chakrabarty

Tanmay Chakrabarty is a former CSE student, currently working as a Senior Software Engineer with 5+ years of experience in the field of Web Application development in PHP+MySQL platform with strong skills in Javascript, JQuery, JQuery UI and CSS. He tries to write notes every week but fails due to heavy loads of duty.

Recommended Recommends


Contact Us