codeigniter captcha Allowed memory

Hi , im tryng to insert captcha in registration , this is my simple controller method :

Code:

public function captcha_setting(){
       
        $this->load->helper('captcha');

       
       $vals = array(
           'img_path' => '.images/',
           'img_url' => base_url().'images/',
       );
       
       
        $data = create_captcha($vals);
       
        $_SESSION['captchaWord'] = $data['word'];
       
        $this->captcha_setting();


        // image will store in "$data['image']" index and its send on view page
        $this->load->view('captcha_view', $data);
     }

If i visit the page captcha_view :

Code:

<?php

echo $image;


?>

I have this error  :

Message: Allowed memory size of 268435456 bytes exhausted (tried to allocate 65484 bytes)