index.php包含在url中时，不显示codeigniter图像

I have created a website using codeigniter. But i stuck with a problem that when i called the link

http://example.com/index.php/about

the images and other files on my assets folder is not showing (due to invalid file path). But it is working fine when i am calling

http://example.com/about

My .htaccess file contain the following code

RewriteEngine on
RewriteCond $1 !^(index\.php|assets|public|\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?$1

and my folder structure is

application
assets
    css
    images
system
.htaccess
index.php
license.txt

Please help me to solve this problem

Lastly i found a solution myself. After adding the following code inside head tag of each view page, i solved this issue.

<base href="<?php echo $this->config->base_url(); ?>" />