php如何去掉二维数组中重复的元素

$arr=array(
"1"=>array("a","b "),
"2"=>array("a","c"),
"3"=>array("a","b")
);
实现结果:

$arr=array(
"1"=>array("a","b "),
"2"=>array("a","c"),
);

function remove_duplicate($array){
 $result=array();
 for($i=0;$i<count($array);$i++){
 $source=$array[$i];
 if(array_search($source,$array)==$i && $source<>"" ){
 $result[]=$source;
        }
    }
 return $result;
}