我如何获得wp自定义标题图像的条件？

I m developing a wordpress theme for wordpress theme directory. In this theme, I have set a custom header image by this bellow at functions.php

$defaults = array(
 'width'         => 1600,
 'height'        => 400,
 'flex-height'    => false,
 'flex-width'    => false,
 'default-image' => get_template_directory_uri() . '/images/lemon.jpg',
 'uploads'       => true,
 'default-text-color' => '95b849',
 'header-text' => true,
);    
add_theme_support( 'custom-header',$defaults);

and I show this header image like bellow:

<div class="header_top_image" style="background-image: url(<?php header_image(); ?>); background-color: #<?php echo get_header_textcolor();?>;">
 <h1 class="header_top_title">
    <a style="color: #<?php echo get_header_textcolor();?>;" href="<?php echo esc_url( home_url( '/' ) ); ?>">
     <?php bloginfo('name'); ?>
    </a>
 </h1>
</div>

In this situation, I want: if not set Custom Header image, This "header_top_image" class's div tag totally don't show.

How I can do that. Actually I thought, there is a function: is_custome_header() , even I search at codex. But not found any function like this which provide if condition. Any body can help me? I need very much this solution. Advance thanks

Actually now I got solution. it will:

<?php
if(get_header_image()){ ?>
<div>Desired div/elements here</div>
<?php } ?>