What do I need to change, Please I receive this a number of times

Notice: Undefined index: image_title in /home/wwwcane/public_html/tiny/wp-content/themes/beaver/header.php on line 131

foreach( $slAr as $sv ){

  $n++; ?><img src="<?php echo esc_url($sv['image_src']); ?>" alt="<?php echo esc_attr($sv['image_title']);?>" title="<?php echo /* line #131 */
  '#sl.lidecaption'.$n ; ?>"/><?php

  $slideno[] = $n;

}