[计] least square filter restoration
zuì xiǎo èr chéng fāng lǜ bō fù yuán ㄗㄨㄟˋ ㄒㄧㄠˇ ㄦˋ ㄔㄥˊ ㄈㄤ lv4 ㄅㄛ ㄈㄨˋ ㄩㄢˊ