Exclude category

Hi there, im using the code of the example 3 as is published at description:

foreach( get_categories(['hide_empty' => false]) as $category) {
    echo $category->name . '<br>';
    echo do_shortcode(sprintf('[wp_custom_image_category term_id="%s"]',$category->term_id));
}

So, i want to exclude some categories, i tried doing it inserting a code on functions.php, but it didnt work. So, how can i achieve this?

Thanks.