如何在php中获取已使用serializeArray追加的数组值

I have normal form along with dropzone.js, images and i am trying to submit it using Ajax.

This is what i have tried so far.

function add()
  {

    var data = $('#add').serializeArray();
    var filenames = [];
    $('.dz-preview .dz-filename').each(function() {
       var names =  $(this).find('span').text();
        filenames.push({name: 'filename', value: names });
    });
    data.push(filenames);

    }

Append works fine,but i got the response something like this.

I can get list of all form posted element by using $this->input->post('unit_id') in controller. How can i access this filename array?

Any help will be highly appreciated.