如何返回上传图像的文件名以插入数据库

有人知道我如何获得刚刚上传的文件的名称，然后将其传递给index（）函数，以便将其插入我的数据库吗？

它是用代码点火器写的，这是我的表单控制器的代码。

谢谢。

public function index() {
    $this->load->library('form_validation');
    $this->form_validation->set_rules('nominee', 'Nominee', 'required');
    $this->form_validation->set_rules('email', 'Email', 'required|valid_email|is_unique[self_nominees.email]');
    $this->form_validation->set_rules('location', 'Location', 'required');
    $this->form_validation->set_rules('category', 'Category', 'required');
    $this->form_validation->set_rules('description', 'Description', 'required');
    $this->form_validation->set_rules('imageupload', 'Image Upload', 'callback__image_upload');
    $this->form_validation->set_rules('videoupload', 'Video Upload', 'callback__video_upload');
    if ($this->form_validation->run() == FALSE)
    {
        //Load the form
        $this->template('form.php');
    }
    else
    {       
        //Run code to add into the database
        $formdata = $this->input->post(NULL, TRUE); // this prevent from XSS attacks
        $this->load->model('users');
        $this->users->self_nominate($formdata['nominee'], $formdata['email'], $formdata['location'], $formdata['category'], $formdata['description'], 'image', 'video');                                    
        //Load the thankyou page
        $this->template('thankyou.php');
    }
}
/*----------------------------------------------------------------
    Image Upload Function
----------------------------------------------------------------*/
function _image_upload()
{
      $this->load->library('upload');
        // Check if there was a file uploaded
        if (!empty($_FILES['imageupload']['name']))
        {
            // Specify configuration for File 1
            $config['upload_path'] = 'uploads/images';
            $config['allowed_types'] = 'gif|jpg|png';
            $config['max_size'] = '100';
            $config['max_width']  = '1024';
            $config['max_height']  = '768';       
            // Initialize config for File 1 
            $this->upload->initialize($config);
            // Upload file 1
            if ($this->upload->do_upload('imageupload'))
            {
                $data = $this->upload->data();
                return true;
            }
            else
            {
                $imageerrors = $this->upload->display_errors();
                $this->form_validation->set_message('_image_upload', $imageerrors);
                return false;
            }
        }
}