$allCats = Mage::getModel('catalog/category')->getCollection()
    ->addAttributeToSelect('*')
    ->addAttributeToFilter('is_active','1')
    ->addAttributeToFilter('include_in_menu','1')
    ->addAttributeToFilter('parent_id',array('eq' => $parentId))
    ->addAttributeToSort('position', 'asc');

Currently, this code showing all category including empty category I want to remove empty category from collection