insert color section on each single Portfolio post

i created a lot of portfolio posts which now should get an colorsection on top:

add_action('ava_after_main_title', function() {
if ( is_singular( 'portfolio' ) ) {
	?>

<div data-section-bg-repeat="stretch" style="background-repeat: no-repeat; 
background-image: url(absoluteURL.jpg); 
background-attachment: scroll; background-position: top center; " class="avia-section main_color avia-section-default avia-no-shadow avia-full-stretch avia-bg-style-scroll  avia-builder-el-0  el_before_av_one_full  avia-builder-el-first  beitragsheader av-minimum-height av-minimum-height-25 container_wrap fullsize" id="av_section_1">
	<div class="container">
		<main class="template-page content  av-content-full alpha units" itemprop="mainContentOfPage" role="main">
			<div class="post-entry post-entry-type-page">
				<div class="entry-content-wrapper clearfix">
				</div>
			</div>
		</main>
	</div>
</div>

<?php
}
});

everything works fine!
But now i thought it would be nice if every portfolio entry of a given Portfolio Categorie gets his own heading image!
But i do not find a hint in source code to what category the post concerns. No Tag_ID nor category by name etc. ??