A

B

C

实际位置

(−40, 30)

(0, 0)

(50, −50)

校正前

(−38.3, 32.1)

(0, 0)

(50.8, −45.4)

校正后

(−39.8, 29.9)

(0.1, 0.1)

(49.8, −49.8)