How to change the output format of category parameters in Joomla component?

Question

laptops

I am developing a component according to the articles of the standard Joomla documentation. I get a list of categories that belong to my component through a request, but I can't process data in json format from the 'params' field into a variable. How to parse a Json array into a regular view.

Below is the code for getting the list of categories:

public function getCatlist(){
        if(!isset($this->catList)){
            $db = JFactory::getDbo();
            $query = $db->getQuery(true);
            $query
                ->select(array('title, description, params'))
                ->from('#__categories')
                ->where('extension = "com_mycomponent"')
                ->where('published = "1"');
            $db->setQuery($query);
            $this->catList = $db->loadObjectList();
        }
        return $this->catList;
    }

As a result, we get the following array print_r($this->catList):

stdClass Object ( [title] => Название категории [description] => Текст описания категории [params] => {"category_layout":"","image":"images\/image1.jpg","image_alt":""} )

Here's how I can convert from json format to the usual one like title and description? How is it recommended to do this?